If we play our textbooks backwards, it seems like the march of progress is inevitable. The larger the timescale, the clearer the pattern becomes. What we miss, though, is the fog of war which inflicts itself upon the casual observer of events. It is often not until years later when the historians or biographers sit down and hash events apart that the truth, or at the very least key facts, may come out. This is not to say historians are always right, but that the observer on the ground rarely understands the greater or lesser significance of events.
For example, any modern summary of the 1968-1969 student strikes at San Francisco State University will draw focus to the creation of the Ethnic Studies Department (ESD), but this outcome would have been far from obvious to a casual observer reading the paper. This is not to say that no-one could have predicted that the strike would win out, or that an ethnic studies department would be created, but that a casual observer might not even have known this was an issue or more importantly THE issue. Playing history forward, we see a sea of activist causes, power struggles, and holiness spirals ending in a negotiated surrender. The ethnic quality of history backwards does not seem to be there when it is played forward. If these events seem to be dusky when we rewind history, when played forward we can see the blackface. What does the strike look like in 2008?
The strike, led by minority students angered by their lack of representation on campus, marked the most violent chapter in the campus’ history, paving the way for student activism around racial issues across the nation. It also fueled the political career of campus president S.I. Hayakawa, who later was elected to the U.S. Senate.
Critics of the strike said some of its goals did not justify the violence. But ethnic studies experts and historians say it brought positive change to the university, particularly the creation of its College of Ethnic Studies, which includes Asian American Studies, Black Studies, La Raza Studies and Native American Studies. [i]
The narrative of this event plays out like much of the text of American history. The pattern plays out thusly: an issue which was extant but of questionable prominence is solved by a conflict. The conflict is then retroactively justified by the outcome. Such is the pattern. This story of conflict, indeed, like most political charged conflicts is the story of a power struggle. Behind the slogans, signs, riots and demands there was a push behind the scenes. It is difficult as with any event in history to trace a singular origin, but I hope I can paint a picture of the series of changes which enabled these eddies to form.
San Francisco State had historically been run by a president. There was some state control, but it had been a mostly autonomous and “autocratic” institution–at least as autocratic as a university can really be. [ii] The State College System as California knows it today didn’t come into existence until 1960, two years before our story begins. Under this new structure, the colleges were governed by a Board of Trustees (instead of the state bureaucracy). The Board of Trustees ran much like the Supreme Court: the governor would nominate the trustees and the state Senate would approve them. [iii] This change, for better or for worse, injected partisan politics into the college system, which doesn’t necessarily entail that the trustees were particularly partisan (I have no evidence one way or the other), but it does mean that actors were more likely to see conflicts as politically partisan, rather than strictly “academic”.
Skipping to 1962, we arrive at the San Francisco State College (later university) to observe an entryist take-over of the Associated Students (student government). The Associated Students’ introductory letter to the 1968-69 student directory can give us some sense of exactly how progressive San Francisco State College was:
It [the student directory] is an organizing tool, a way for us to come together and identify ourselves, our purposes and our rights. Only by coming together can we make this college function in a truly democratic manner and make it responsive to the needs of all people. Liberty, Fraternity, Equality. [iv]
At one point, some enterprising progressive students figured out that the Associated Students controlled over a million dollars (the exact amount is a subject of debate). That may not be surprising today, but keep in mind these were 1962 dollars–or over 7.8 million dollars in 2016 dollars. [v] With control of the budget, the radical students looked near the campus for opportunities to spend student fees.
In 1964, the Associated Students used the budget to fund a Tutorial Program which was designed “…to address the inadequacies of the education given to students of color that made most “unqualified” for admission to the college.” [vi] The programs concentrated on helping students with basics skills such as reading, math, and staying in school. [vii] They also started a Community Involvement Program (also funded by the Associated Students) and brought in San Francisco State faculty to facilitate “…active community participation in the Tutorial Programs, and address issues impacting housing and employment.” [viii] These programs focused on the ghettos and slums near the school. [ix] As Eric Solomon (a radical socialist Professor at SFSC) indicated, the purpose of these programs was to bring “third-world students” to campus. He further comments: “It was community based…And they were indeed very, very – some of them, skilled organizers.” [x] Within the next year the Tutorial Program had spread to a dozen sites with hundreds of volunteers. The students running the program tended to be heavily religious Catholics, Quakers or Jews and many had already been involved in civil rights. [xi]
That was the start of the Fillmore tutorial program, which began in a small Baptist Church on Divisadero Street with about $20 in Associated Students funds, and expanded to 22 centers involving more than 500 college students just before the student strike. [xii]
Among the many programs focused on the ghettos near the school, perhaps the most important was yet to come. Associated Students would on January 30, 1964, approve the creation of the Negro Student Association (renamed Black Student Union or BSU). [xiii] This group would soon embroil itself in the plans of the Associated Students.
The Donahoe Higher Education Act of 1960 was a comprehensive master plan for higher education in California. Besides the restructuring of the governance of the state college system, the plan had reorganized the enrollment criteria. The master plan had created limits on who could enroll at the State-college campuses. Only the high school students ranking in the top third of their graduating classes could enroll. Furthermore, in 1965, performance on the SAT was added to admission requirements. San Francisco State College, like other state colleges, was meant to take students who didn’t qualify for the University of California schools, but who needed something better than community colleges. The increase in the stringency of the requirements had the predictable effect of reducing minority enrollment (the black enrollment rate was reduced from 10% to 4%), something the BSU would quickly take notice of. In a city which at the time was well over 50% minority, these policies left a lot of warm bodies out in the cold. [xiv] [xv]
SFSC wasn’t an Ivy, nor a top-level university, nor was it isolated from poverty. SFSC was an unprincipled exception without the authority to maintain its position. Whereas Harvard could draw on the elite and get away with, it SFSC did not have that authority. [xvi]
Itching to spend more of their classmates’ money, in 1966 the Associated Students decided to start the first experimental college. Guest professors would come to campus and teach for a semester. They included Paul Goodman, Harold Taylor, and Saul Alinsky. [xvii] Eschewing traditional topics, they focused on more “relevant topics” like sex, revolution, drugs, guerrilla warfare, and socialism: topics that irritated tax payers and legislators alike. [xviii] By drawing in the interested progressive students to the Experimental College, radical students grew a trained and primed base with which to attack the college. According to our friend Eric Solomon, of the ~16,000 students only 200 to 400 were radicals (on the Maoists to Trotskyists spectrum, according to Solomon). These students were largely, as Solomon puts it, “leftovers of the Experimental College.” [xix]
While Tutorial and Community Involvement Programs seemed to serve as recruiting tools, the Experimental College served as an introduction to radical politics. The community organizing focus gave students and non-students alike the language and tactics which would later be employed on campus. As the Experimental College took off, the character of the programs (Tutorial and Community included) shifted away from the SDS (which had come to the campus in 1966) style of progressivism toward Black Nationalism and Third World Liberation ideology and format. [xx] [xxi]
In addition to reading radical, revolutionary, and Marxist literature, the BSU was in close contact with CORE, SNCC, NAACP, NUL, and the relatively new Black Panthers. This collaboration bore out in the militant language employed by the BSU, which often echoed the rhetoric employed by other organizations. [xxii] One of the most experienced members of the BSU was a veteran of the SNCC. The same year the SDS came to SFSU (1966), James “Jimmy” Garrett arrived at SFSC. Garret possessed experience from working as an organizer for the SNCC in Watts and the South, as well as a singular purpose. Jimmy Garret had come to organize. First on his agenda was to change the way the BSU regarded themselves. [xxiii]
In trying to organize the BSU, said Garrett, it was necessary to teach the students that they were oppressed. “They are educated to believe that they are not over oppressed, and if they get an education they can be not oppressed at all.” [xxiv]
These ideas coincided with trends springing from across the country. The more the BSU felt itself oppressed, the more it could build pride. The Experimental College served as a medium to propagate these themes not only to the BSU, but to the white radicals. Garret even taught a course at the Experimental College. In late 1966, the Experimental College hosted the Black Arts and Culture Series. According to a then-student Margaret Leahy:
The spring of 1966 saw the development of two more precursors to the 1968-69 Strike: the emergence of the Black consciousness movement and the Experimental College. Black pride was not only manifest by wearing Afros and dashikis, but in Experimental College-sponsored classes on Black Nationalism and the AS-funded Gallery Lounge performances by Black performers. Students discovered a new reality, one not offered as part of the traditional White, Eurocentric curriculum. Students also inserted themselves into their education through student-run course evaluations that assessed the relevancy of course content and the effectiveness of instructors. [xxv]
Garret knew, as any good organizer does, that he needed power, and so the Tutorial Program caught his eye. The Tutorial Program already focused on the ghettos near the school. If the Tutorial Program was already educating black children, what could be a better venue for Jimmy Garret to spread the BSU’s influence? Timothy J. Sampson, who would join the staff at SFSU soon after the strike, describes the tactics of “organizing” as such:
Alinsky had ways of thinking and talking about that that I think are very helpful. I mean, he was fond of saying that power is a neutral concept and power simply refers to the ability to act – to do what you want to do. He talked about power as flowing from on the one pole, money, and on the other pole, people. Those were the classic poles. So if you don’t have money, you have to have people – and kind of a further extension, lots of people. [xxvi]
The AS had money and their programs had people. How does one acquire an organization? Timothy Samson explains:
The notion that you can build a strong people’s organization by simply one-by-one, you’ll start one-by-one putting people together, is also fictional. People are already – as Alinsky was fond of saying, people are already organized. The job of the organizers is to find out how they’re organized and use that knowledge and change those patterns to put those pieces together in a stronger way… The [organization] church joins – he doesn’t go to a church and get one or two members to join; he goes to a church and gets the church to buy in as a congregation. He goes to a soccer club in a Latino neighborhood and gets the soccer club to join the organization, not individual people off the street. [xxvii]
Garret put together his first plan of attack in May of 1966. Through his “power analysis” he concluded that he needed to target the Associated Students and then the Tutorial Program. [xxviii] Naturally, the AS was hardly an enemy to the BSU; they were quite sympathetic, but a sympathetic ally isn’t as good as power. Where does power grow from? Well, Mao was all the rage down in Fillmore. Garret and the BSU devised a strategy that they would use over and over again.
That summer Garrett was elected chairman of the BSU Garrett led the BSU in a series of funds demands. At this time most of the liberal-radical coalition that dominated student government for 6 years was going through this “Gosh, am I a white racist after all?” thing. The blacks would come in with pretty inflated demands, and there were some wild [verbal] battles. Lots of rhetoric, lots of packing the rooms with more blacks than whites, inexplicit threats. We learned how to have meetings while people pared their fingernails with their switch- blades. (Garrett denied any switchblade knives were ever used, pointing out that they are illegal in San Francisco.) [xxix]
A switchblade is no gun but it will do in a pinch. Was that irony or insincere irony? Illegal possession of firearms is, well, illegal, and the BSU seemed to have no qualms with breaking those laws. [xxx] [xxxi]
The white liberals, most of whom felt themselves personally committed to the black cause, agonized over what to do, the legislator said, and finally “we decided to hang tough.” [xxxii]
First, play on their conscience; if that doesn’t work, threaten them, and if that doesn’t work? Then:
Garrett: “Sure, but we didn’t use any switchblade knives. . . . I’m not saying nobody ever got jumped on, but nobody ever got jumped on at a meeting.”[xxxiii]
Importantly, Garret brought militancy home to the BSU, and if Garret would “jump” his allies, what would he do to his enemies? The AS was already enthralled with the BSU. Garret’s “request” seemed to scratch that messiah complex itch. The AS handed over the program they had worked tirelessly to build. By the end of the summer of 1966, the BSU had partial control over the AS’s baby, the Tutorial Program. By 1967, two-thirds of the leadership were BSU. With the Tutorial Program largely under their control, the BSU began to look for other opportunities. [xxxiv] [xxxv]
…they began to settle down to work projects, different kinds of projects, like how to cut out racism in different areas on campus. Finding out what classes were racist. What teachers were racists. [xxxvi]
The BSU and Garret were watching how other campus student riots had played out. They concluded that violent occupation of buildings had not played out well for the students. It usually ended with the students in jail. What the BSU needed was both plausible deniability and prolonged conflict. Ben Stewart described the strategy:
“We call it the war of the flea . . . what does the flea do? He bites, sucks blood from the dog, the dog bites. What happens when there are enough fleas on a dog? What will he do? He moves. He moves away. He moves on. And what the man has been running down on us, he’s psyched us out, in terms of our manhood. He’ll say, what you gone do, nigger? You tryin’ to be a man, here he is with shotguns, billy clubs, .357 magnums, and all you got is heart. Defenseless. That’s not the way it’s going to go any more. We are the people. We are the majority and the pigs cannot be everywhere, everyplace all the time. And where they are not, we are. And something happens. The philosophy of the flea. You just begin to wear them down. Something is always costin’ them. You can dig it … something happens all the time. Toilets are stopped up. Pipes is out. Water in the bathroom is just runnin’ all over the place. Smoke is coming out of the bathroom. “I don’t know nothin’ about it. I’m on my way to take an exam. Don’t look at me. . . .When the pig comes down full force, ain’t nothin’ happening. He retreats. When they split, it goes on and on and on. . .” [xxxvii]
The most prominent part of our story of the SFSC strike was the protests. The number of protests, demonstrations, or other forms of complaint are too numerous to count. By necessity, I can only provide a taste of these events. Our initial protests centered on the Vietnam War: specifically the cooperation of the college with the Selective Services. During this time, the school was required to and did report on male students’ academic status. This was necessary to figure out which students were enrolled and therefore could be exempt from the draft. The Associated Students passed a resolution requesting that the administration stop reporting academic standing to the Selective Services. The president of SFSC, John Summerskill, was fairly new, friendly, liberal, and sympathetic to the requests of the student radicals. As Professor Eric Solomon describes him:
“We had, by that time, a new president [of the college], John Summerskill, a liberal from Cornell, a psychologist. A sweetheart. I liked him always very much, and thought he was a good man. One of the weakest men I’ve ever known as well.” [xxxviii]
Despite his sympathies, Summerskill didn’t accept the resolution and in turn, the students staged a small “sit-in” in the president’s office (May 2nd). [xxxix] As it turned out, his hands had been tied by the Board of Trustees; he could not accede to the students’ demands, even though he wanted to. Even when the Academic Senate voted to end cooperation with the Selective Service, Summerskill still could do nothing. The Board’s overruling of the president would become a sore spot with professors and students alike. This was especially true of the American Federation of Teachers (AFT), one of the unions on campus. Professors were especially used to getting their way by making nice with the president. The shifting of power to the Board of Trustees had brought this arrangement to an end. Art Bierman had founded the AFT union on campus years ago (1959), and it had quickly become a popular vehicle for guiding policy. The AFT was used to getting its way with the college administration. This rebuff by the Board of Trustees would soon make them a subject of much vitriol. [xl] [xli]
Far from being focused solely on the BSU the issues de jour, protests’ subjects were as various as: “Vietnam War, the Black Students Union, student power, student-faculty relations and other activist topics” including free speech and the always popular racism. [xlii] While the SDS, PLP, etc., were allied with the BSU, they were by no means of one mind. The SDS and PLP had their own issues to pressure the administration with.
By 1967, the Tutorial Program, Community Involvement Program, and the Experimental College had “graduated” quite a few students. [xliii] This had attracted the attention of the Carnegie Foundation, which was prepared to provide and additional million dollars in scholarship grants to bring these unqualified students to campus. [xliv]While the Carnegie deal was still being discussed, the Board of Trustees authorized the President, after some BSU rabble rousing, to increase the number of students who could be admitted without being qualified, under the Educational Opportunity Program, from 1% to 2% of the student body. [xlv] This was just another drop of blood in the water. The BSU pressed administrators to use the program to admit more black students, particularly ones they chose. As soon as the BSU had confirmed their candidates were admitted (for the 1967 school year), they put them through a BSU orientation with readings from a slew of radical authors. [xlvi]
As events would have it, the editors at the student newspaper The Gater were not fans of this idea of accepting the Carnegie grant. Was it the unqualified nature of the students? Had they observed the radicalism coming out of the Tutorial Programs? Who knows, but they made the mistake of writing an editorial against the grants. On November 6, 1967, a group of BSU students walked into the office of The Gater and confronted James Vaszko, who was on the phone and told them to wait one second:
On the morning of November 6, 1967, a group of black students entered the office of the Gater, a student daily newspaper, and beat and kicked the editor. A Gater photographer took spectacular photos of the ensuing melee between blacks and newspaper staffers. The Black Students Union denied having any part in the beating, but the photos in the Gater the next morning showed that BSU members comprised the attacking force. [xlvii]
Six students, including George Murray, (who will be very important later) were suspended, and the same number were arrested. This student suspension raised the ire of the radical students against John Summerskill. Summerskill was too soft on the Vietnam War, had suspended yet another radical student, and of course, had suspended the students involved in assaulting The Gater staff. This friendly liberal professor managed to inspire large student demonstration for his “liberalism”. Did these demonstrators ask for a College of Ethnic Studies or the laundry list of later BSU demands? No. They carried signs about generic issues like free-speech, racism and the Vietnam War: all the bread and butter of the SDS. For Summerskill, these protests were the “inevitable” results of an “urbanized society.” [xlviii]
“I do not think we will see peace on our campus until we see peace in our cities, peace in Vietnam,” –President Summerskill
This tone will become a pattern among our campus denizens. Indeed, it is one recognizable in any era. Don’t try and stop the violence, violence doesn’t work, accede to their demands. They’re not my demands, but really that’s the only way to end this.
The “by any means necessary” tactics of the SDS and BSU are epitomized by the other events of the morning of Nov. 6, 1967. Before the scuffle at The Gater office had even begun, there was already action on campus. As one student describes his memories of that morning:
“I was a sophomore back then, just turned 19 years old when, on the morning of Nov. 6, 1967, I awoke in my fifth-floor room to a screaming fire alarm. I figured it had to be a prank. But residents on the other side of the hallway saw smoke and flames rising below their windows. So we put on our slippers and bathrobes, and raced down the fire escapes. On the ground, we found smoke and fire spewing from the windows of the dormitory lounge, a one-story add-on that faced the street. By then flames rose 20 or 30 feet above the roof. The logbook of the San Francisco Fire Department states that three fire companies appeared at Merced Hall at 6:17, 6:24, and 6:27 a.m. The fire left the lounge a blackened, roofless, windowless wreck, but there were no injuries. Rooms on the first floor suffered smoke damage, but the main structure of Merced Hall stood unscathed. The quick response of firefighters and the building’s concrete construction prevented the fire from spreading, but had the fire escapes been blocked, hundreds would have suffocated.” [xlix]
The third alarm fire caused $100,000 dollars in damage, but fortunately hurt no one. [l]
So far, we are a year out from the student strike. If we are to understand the justification for the strike, it was justified because of the eventual creation of the ESD. Yet, here we are a year out, and the ESD is no more THE issue than the dozens of slogans echoing about the campus. What were the reactions to these events? One month after those students walked into The Gater’s office, what were the students talking about? The only direct reaction to the suspension of these students seems to be the creation of the Movement against Political Suspensions (MAPS) by the SDS. MAPS was concerned with due process and free speech: a front group with which to rally moderate students.
Planning their revenge for the suspensions, the SDS and the BSU planned a “rally”. Jimmy Garret, a BSU leader, promised to bring a small army of 5,000. Whether those numbers materialized is doubtful, but the rally left its mark. While the SDS continued to insist the event was a “peaceful protest”, the BSU continued to employ violent rhetoric, which would soon get them in hot water. The BSU’s statements of “by any means necessary” and “no hassle about tearing it up” are better descriptors of the resulting protest than peaceful. [li]
On December 6, 1967, this coalition stormed, once again, into the administration building. Anticipating this sort of response, the doors were locked. In a wholly uncoordinated fashion, the mob proceeded to both break in through a 2nd story window and smash through the glass doors on the ground floor. Students joined by the BP and a professor of international relations held their protest in the otherwise empty building. [lii]
“Summerskill was in his office with two representatives of the San Francisco Police Department. There were 200 police waiting a call in an apartment complex near the campus. President Summerskill and his police advisers decided to close the campus and not risk bringing police on campus to battle the mob. Fist fights broke out between students and nonstudents, and the crowds dispersed after about 3 hours without rioting.” [liii]
Of course, “without rioting” completely depends on your definition of rioting. Unopposed, the protesters attacked bystanders across campus, stole from the bookstore, set a small fire, ransacked the 2nd floor of the administration building, and threatened students to disperse classes (in other buildings). [liv]
Unfortunately for Summerskill, videos of the mobs breaking through the glass appeared on televisions across the state. The police department representatives requested to be removed from the reports, which only made the situation worse. A few politicians (likely spurred by angry calls) even called for Summerskill’s firing. Needless to say, the Board of Trustees soon called to chastise Summerskill. [lv] While we cannot know what the police representatives were thinking, it was very clear that Summerskill both feared and sympathized with the mob. Summerskill would rather no students have classes than arrest the students disrupting the campus. Summerskill was not a fan of discipline, as he had previously stated.
“Discipline has been maintained on our campus. Discipline isn’t going to solve the problem that 80 percent of our students are opposed to the Vietnam War.” [lvi]
If this seems like the beginning of a long battle for the right of ethnic studies, you’d be wrong. Despite its violent and rash tactics, the BSU got what it wanted. In fact, later that year (1967), Summerskill would accede to the demands of the BSU to create a Black Studies Department (the eventual ESD). Keep in mind, the justification for the violence and upset which would come is the eventual creation of the College of Ethnic Studies. Yet, before the first day of the strike (November 6, 1968), the president had already agreed to work on creating what would become the Ethnic Studies Program. The BSU was still a side show at this point. This was a conflict with the administration which was as much about “free-speech”, the Vietnam War, firing of a professor and abuse of power, as it was about race. [lvii] [lviii]
For most reasonable people, this would seem to be the end of it. The BSU broke people and things asked nicely and got what they wanted. For the progressive slate, there is no salvation. There was an army and, whether or not it was senseless, there needed to be conflict. Couched in the language of Third World Liberation, the BSU complained that the Black Studies Department was not sovereign (able to control its own budget). Summerskill had handed over the program to the departments, which controlled hiring of instructors and the content of the classes. It was not enough that such a program existed, but it must be controlled by the BSU or their allies. What the BSU wanted was an autonomous, fully-funded department which could hire professors at will to teach a steady supply of students with special qualifications. They already had a pipeline, but the BSU was looking to expand. [lix]
Summerskill’s unwillingness to act would not endear him to either the trustees or the students, as his sympathy to the students was an unrequited love. [lx] If letting the students (and professors) run wild was not enough, what could assuage them? Perhaps Professor John Gerassi can help us?
“…a result of that hearing we could really begin to talk about the real causes for the unrest in general. They can get rid of me, they can rid themselves of other student leaders, they can get rid of Black Student Union leaders, the unrest will continue unless the causes are coped with in some way, tackled.” [lxi]
Professor John Gerassi is thoroughly unhelpful. We must “cope with the causes?” I’m hearing an interesting tone. Keep speaking power to truth Professor Gerassi:
“The first act of violence, was in locking the door against us. What we did was an act of self-defense and self-expression.” [lxii]
The natural response to political violence is to chastise the responsible parties. If radical socialists, professors, and students tear up your campus you attack those same groups. However, John Gerassi and indeed John Summerskill come from a long tradition and preferred the unnatural response. The unnatural response is to look at the grievances of the attacker and chastise the victim. This unnatural response typically employs the passive voice; after all we wouldn’t want to blame the attackers ergo: “unrest will continue unless the causes are coped with”. This long tradition was practiced by the members of the Academic Senate as well. President Summerskill’s tolerance and understanding were very popular. The Academic Senate gave him standing ovation and even a supermajority vote of confidence. [lxiii]
[vii] Bunzel, John H. , “Black studies at San Francisco State,” The Public Interest, 13 (Fall, 1968), 22-38. http://www.nationalaffairs.com/doclib/20080522_196801302blackstudiesatsanfranciscostatejohnhbunzel.pdf
[ix] Bunzel, John H. , “Black studies at San Francisco State,” The Public Interest, 13 (Fall, 1968), 22-38. http://www.nationalaffairs.com/doclib/20080522_196801302blackstudiesatsanfranciscostatejohnhbunzel.pdf
[xv] The Black Revolution on Campus By Martha Biondi
[xvi] Bunzel, John H. , “Black studies at San Francisco State,” The Public Interest, 13 (Fall, 1968), 22-38. http://www.nationalaffairs.com/doclib/20080522_196801302blackstudiesatsanfranciscostatejohnhbunzel.pdf
[xlvi] The Black Revolution on Campus By Martha Biondi
[lix] Bunzel, John H. “Black studies at San Francisco State,” The Public Interest, 13 (Fall, 1968), 22-38. http://www.nationalaffairs.com/doclib/20080522_196801302blackstudiesatsanfranciscostatejohnhbunzel.pdf