My first book, The Physicists, was conceived when I. I. Rabi visited Princeton in 1961–1962 as a Shreve Fellow in the History Department (see Kevles Reference Kevles1995). Some two years earlier C. P. Snow had published his influential provocation, The Two Cultures and the Scientific Revolution, and the academic world was abuzz with initiatives aimed at achieving better literacy in science among liberal arts majors. Rabi was a Nobel laureate in physics at Columbia University and his visit was one of Princeton's efforts to this end. It had been arranged by my mentor, Eric F. Goldman, a historian of modern America who had gotten to know Rabi through their mutual engagement with current issues in American democracy.

Rabi was an impishly warm man with a shrewd understanding of human affairs and an avid interest in history. He was extensively experienced in the high councils of science and government, having been a key figure in the wartime mobilization of physics, including microwave radar and the atomic bomb project, and having served on the General Advisory Committee of the Atomic Energy Commission and on the President's Science Advisory Committee. The Shreve Fellowship had been established to foster historical studies that would ascertain the reasons for the “decay, degeneracy, extinction and destruction” of nations, as Eric gleefully pointed out to me. The idea behind appointing Rabi to the post – he was the first non-historian to hold it – was that he would help the humanists at Princeton learn how better to integrate science and its culture into their courses (presumably, one supposed, to forestall the decay of American civilization in the late twentieth century).Footnote ¹

I had majored in physics at Princeton and encountered Big Physics even as an undergraduate, working as a research assistant to Gerard K. O'Neill, a member of the physics faculty who was involved with the Princeton-Penn Accelerator, and then spending a summer with Gerry at Stanford, where he was developing the apparatus for colliding beam experiments with Wolfgang Panofsky. I was fascinated by the enterprise of Big Physics – my first published article was a profile of Gerry in the Princeton Alumni Weekly – by its resources, capacities, and scientific purposes, but I was made restless by the prospect of a career in large-scale, corporatized science.

I found history and writing more appealing, in no small part as the result of taking Eric's celebrated course in Modern America (my friends in the liberal arts had told me that it was a must, even for a physics major). I first got to know Eric by participating in a course project to rewrite the U.S. Constitution, adapting it to the realities of the welfare state and the country's commitments to collective security in the nuclear age (the idea of modifying the sacred document aroused scandalized comment in some quarters of the country). The experience prompted me to think about becoming a historian. Eric put me in touch with Charles C. Gillispie, who taught persuasively that science has a history that merits study. But not least – though not only – because of Eric, I wanted to work in American history. After getting my degree, in 1960, I spent a year studying history at Oxford – it seemed like a good idea to learn some European history, too – with the good fortune of having the historian Alan Bullock, Hitler's biographer, as my tutor and Alistair Crombie, a leading scholar of medieval science, as my guide in the history of science.

In 1961, I returned to graduate work in history at Princeton to study under Eric, thinking in some vague way that I might combine my interests and knowledge by studying the history of science in America. The subject was of little concern to most historians at the time, including historians of science, not least because science in the United States was taken to be a historical backwater, operating without distinction in the shadow of Europe. But Eric encouraged my inclination towards it. His graduate seminar, the year I took it, was devoted to the domestic history of World War I and was organized around writing a major research paper. Mine concerned the wartime use and postwar impact of intelligence testing in the American army and it eventually became my first scholarly article (see Kevles Reference Kevles1968).

What prompted my focus on the history of physics in the United States was sitting in on an informal discussion group of scientists and historians that Eric and Rabi established during Rabi's visiting year to explore the rise to power of science, especially physics, in the United States and its relationship to the larger society. The group, which met every couple of weeks or so at Rabi's Princeton home, included J. Robert Oppenheimer, who in the 1930s had created the nation's first school of theoretical physics, led the wartime effort to build an atomic bomb, and through the early 1950s was an exceptionally high-profile adviser in nuclear policymaking; Henry DeWolf Smyth, the author of the authoritative postwar report on the technical aspects of the atomic bomb and later a member of the Atomic Energy Commission; John A. Wheeler, one of the world's leading theorists of general relativity; the chemist Donald Hornig, who would later serve as Science Adviser to President Lyndon B. Johnson; George F. Kennan, perhaps the most influential figure in the shaping of postwar American foreign policy; and Charles Gillispie.

Eric had arranged for me to attend the gatherings and to write a paper for the group sketching out a course in modern American history that would integrate the development and role of science into the national narrative. The group's meetings were eye-opening, rare encounters with living history and proved to be one of the most influential elements in my graduate education. I gained specific information from them, of course, but, still more important, insight into their culture and experience as the scientists among them attempted to account for how they had progressed so rapidly in both task and sensibility from the exploration of subjects such as nuclear structure and quantum field theory to building atomic bombs, dramatically escalating the destructiveness of war, and riding the bronco of the postwar nuclear arms race.

By the time the meetings ended, I was fixed on the idea of writing my dissertation, and eventually a book, on how physicists in the United States had risen to world prominence and become an important power group in American society. This story, which reached back into the nineteenth century, was largely untold, and I thought that if it was populated by the kind of people in the Rabi discussion group, the tale would surely be fascinating in and of itself and perhaps bridge the two cultures. Towards that latter purpose, I intended that the book would both satisfy the rigorous requirements of historical scholarship and appeal to a general, educated audience. I saw no conflict between the two goals then, nor have I discerned any since.

I left Princeton, Ph.D. in hand, in June 1964, first for a brief stint with Eric on the White House staff – he was Special Consultant to President Johnson – and then to an assistant professorship in the humanities faculty of the California Institute of Technology (Caltech). Once I managed to devise the courses I was to teach and learned how to teach them, I began to develop my dissertation, which covered physics in the United States from the Civil War to World War I, into what became The Physicists.

My aim was to write a history of the physics community that would combine multiple subjects – professional, intellectual, social, institutional, economic, and political history. I knew of no models to follow, especially for such a topic set in the United States, so I invented my way forward. In my dissertation I had defined the community for myself by establishing a prosopographic profile avant la lettre, at least in the history of science, identifying its members and analyzing their career trajectories, using whatever biographical materials I could get.

The numbers told me that, while the American physics community grew a good deal in the later nineteenth century, it was still small in the early 1900s, a fact that, along with a lack of theory and an alleged national indifference to basic science, seemed to account for the weakness of physics in the United States. But then Paul Forman, John Heilbron, and Spencer Weart published their Physics circa 1900, a quantitative survey of the number of physicists at work in Germany, France, the United Kingdom, and the United States as well as of the funds and laboratories available for research (see Forman, Heilbron, and Weart Reference Forman, Heilbron and Weart1975). Its results were striking, revealing that the number of physicists in the U.S. and the resources available to them were not much different from numbers and resources in Europe. Neither, according to my own statistical survey, were the research topics – for example, electricity, magnetism, and heat – on which they were publishing.

The results prompted me to think about the structure and practices of the American physics community in the later nineteenth century with an eye to finding in its arrangements for intellectual governance reasons beyond the lack of theory for its relative weakness in the world rankings, even in experimental physics. That exploration led to the sociology of science and history done with sociological sensitivity, particularly the works of Robert K. Merton and his students at Columbia, especially Harriet Zuckerman and Jonathan Cole, and the books of Joseph Ben-David, Sally Kohlstedt, and Thomas Kuhn (cf. Zuckerman Reference Zuckerman1977, Merton Reference Merton and Storer1966; Cole and Cole Reference Cole and Cole1973; Ben-David Reference Ben-David1971; Kohlstedt Reference Kohlstedt1976; Kuhn Reference Kuhn1962). The take-away for me was that science is an elite enterprise, in which a large fraction of intellectual advance in a field is produced by a small fraction of its practitioners. I added to the take-away my own view that the members of the elite tended to possess what Rabi called a “taste for good science” and that they needed some institutional means to encourage good taste in their disciplines. In the late nineteenth century, geology in the United States was not a backwater but was practiced with world-class distinction, and a comparison of the structures of intellectual governance in physics and geology showed why the one was strong and the other comparatively weak.

Since I aimed to integrate multiple topics into the book, it made good sense to draw on a broad range of secondary works that went beyond the history of science as such and – reflecting, I suppose, my training under Eric, in a history department – of diverse primary sources, including private manuscript collections, university and philanthropic archives, scientific papers, memoirs, and newspapers and magazines. Serendipity, in the form of my happening to be at Caltech, provided access to two crucially significant caches of manuscript – the papers of the astrophysicist George Ellery Hale, an enormously influential statesman of American science, and Robert A. Millikan, the nation's second Nobel Laureate in physics and a key figure at the intersection of physics, academia, industry, and government. (The Hale papers, which were at the Pasadena offices of the Mount Wilson Observatory, had been somewhat used by scholars; the Millikan papers, which occupied multiple old file cabinets in the basement of a Caltech lab, to my knowledge, not at all. Along with using both collections extensively, I edited a 100-reel microfilm edition of the Hale papers that is now available in a number of libraries around the world and arranged to have the Millikan papers organized and catalogued. I also obtained a small grant to establish a Caltech archive from Lee DuBridge, the Institute's president, who responded immediately and with enthusiasm to the proposal.)Footnote ²

I also made use of interviews, some of which had been done by other scholars – of special importance were those in the Archive for the History of Quantum Physics, a joint effort of Thomas Kuhn, Paul Forman, and John Heilbron – a number of which I conducted myself. My first interviews were not all that productive because my questions were too general (“Tell me about your career in physics”), yet at least one of them – a conversation with Edward Teller, in the spring of 1962 when I was writing my dissertation – was altogether the opposite, in more ways than one. Teller had recently been a guest on Eric's “Open Mind,” a weekly NBC television talk show that he moderated and that was sometimes given over to a conversation with a single individual. Teller, a hard-line anti-Communist, was known as the father of the hydrogen bomb and, among liberal scientists, as a knife-in-the-back witness against Oppenheimer during his security hearing, in 1954. Eric asked Teller about Oppenheimer as a security risk. Teller sat tight-lipped, saying nothing for the better part of a minute, after which Eric turned to other subjects. Teller demanded that Eric's question and his silence be cut from the program, which had been taped, before it was broadcast. NBC agreed over Eric's vigorous objections, but when reporters called to ask what had been edited out, Eric told them, making Teller's silence front-page news the next day.Footnote ³

When I got to Berkeley, Teller invited me for our chat to his home. We sat in his living room, a large round coffee table between us, and his wife, Mitzi, served me freshly baked chocolate chip cookies and a glass of cold milk. Our talk went pleasantly enough until Teller discovered that Eric was my doctoral supervisor. He told me that he had been under no obligation to answer Eric's question about Oppenheimer. I said that I agreed, thinking, though, that he had no right to suppress the fact that he had refused to answer the question. Not wanting to antagonize him, I kept that thought to myself, preferring to ask him about his testimony against Oppenheimer at the security hearings. He declared that Oppenheimer had been a pro-Soviet Communist. I countered that no one had ever produced a shred of evidence that Oppenheimer had been a card-carrying member of the Communist Party. He drew himself up and, wagging his finger at me over the milk and chocolate chip cookies, averred in a low but heated voice, “Young man, you don't understand that the Communists don't give cards to their most important agents.”

The conversation taught me that interviews could be dramatically informative, not least about the beliefs, attitudes, and character of the interviewee. I also eventually realized that what made the encounter with Teller so revealing was that it centered on specific, concrete topics – Eric's program and Robert Oppenheimer's alleged political commitments. I thus sought to make interviews useful by coming to them with specific questions that arose from extensive previous research, and I adhered to that approach in the numerous additional interviews I've conducted for most of my books since.

Trying to integrate all the material I was gathering into a readable history that would appeal to both historical scholars and a broad general audience was a challenge all its own. I found inspiration and guidance to this end in Eric and his work. He was a brilliant writer whose books and essays were grounded in meticulous scholarship and appealed to a wide readership. If you want to write well, he would tell me, read good books, pay attention to how the authors do it, and write a lot. He often stressed that the reader could close the book at any time.

While attending to scholarly rigor, I made a point of trying to keep the reader interested by writing history that told a story while weaving analysis into the tale. I drew literary instruction from first-rate historians but also from novelists and journalists, some of them fast friends. Particularly influential among them have been Hugh Nissenson and Jane Kramer, each a master of the melding of craft, content, and the revelation of character. I sought to enliven my narratives by incorporating vignettes of historical actors high and low, bearing in mind the advice that Charles Gillispie once offered – that it is far better to see into people rather than through them.

I was advantaged in my scholarly purposes by being at Caltech. The Institute, while a powerhouse in science and engineering, was the opposite of intimidating. It was an informal, welcoming place, a kind of republic of science, where faculty at all ranks from the president on down were on a first-name basis and people cared not about who you were but what you had to say. I knew from the Rabi discussion group that many physicists were remarkably interesting and thoughtful human beings, and my life at Caltech, where I regularly lunched and partied with scientists, steadily reinforced that impression. To be sure, some were indifferent to the writing of history – Richard P. Feynman seemed, uniquely, contemptuous of it – but many of them liked to talk history, including history of science. A number of the physicists – for example, Lee DuBridge, Robert Bacher (the Institute provost), Carl Anderson (the chair of the Division of Physics, Astronomy, and Mathematics), and Robert Christy (a later provost) – were prominent members of what I came to call the Los Alamos generation. I picked up from them a rich store of their experience and lore, some of which made its way into my book but much of which informed my historical understanding.

The content and interpretation of the book was also shaped by what was happening in the world at large. It was clear from the outset of my work, if only from talking with Rabi, that the entrance of Jews into American physics was a salient part of the story of physics in the United States of the twentieth century. But the emergence of the civil rights and the women's movements prompted me to address in the book the issue of why through the second third of the century American physics included so few blacks, women, and Roman Catholics. Here I profited from the pioneering work of Margaret Rossiter on women in American science and from studies by several sociologists on the historical relationship of Roman Catholics to learning in the United States. I was also sensitive to the social upheavals of the 1960s and early 1970s as they bore upon the power and standing of physicists in American society, notably the indictment of the military-industrial complex, the open resistance to the development of anti-ballistic missiles, the attack against nuclear power, and President Richard M. Nixon's dissolution of the President's Science Advisory Committee. Physicists in the United States obviously commanded a fragile power and I was stimulated to deepen my thinking about the broad sweep of the community's development, including the problems that an elite of knowledge had long faced in the American democracy.

A significant part of The Physicists deals with science and government in the United States. Some of my most rewarding research was in the records of federal agencies and the congress, including congressional hearings. I was avidly interested in politics (I remain a political junkie to this day) and knew something about the workings of politics and government from direct experience – my stint on the White House staff and then in California my intermittent involvement in presidential and state campaigns. On the scholarly front, A. Hunter Dupree's pioneering classic, Science in the Federal Government, provided a solid historical starting point, and my thinking was also shaped by the political scientist Don K. Price, who was attentive to the inevitable tensions in the United States arising from the preference for autonomy of an elite of special knowledge and lay insistence on democratic control of the affairs of government (see, for example, Price Reference Price1965).

Then, too, at Caltech I was in the Division of Humanities and Social Sciences (the Institute, which has no departments, is organized into six interdisplinary divisions). I learned a great deal from my colleagues about economic and political ways of thinking – concerning, for example, investment in public and private goods and interest-group politics at both the congressional and federal levels – that contributed to my understanding of science in the American democracy. Since Caltech had no graduate program in history and its undergraduate history curriculum was marked by a lot of flexibility, I was able to teach the book I was writing, a practice I have followed with subsequent books. Trying to explain things to undergraduates imposes its own clarifying discipline on the presentation of a subject.

I spent some ten years writing The Physicists, and being among a small vanguard of the social history of science I ran into discouragements of various kinds. I was then – and for more than a decade afterward – the only historian of science at Caltech. I found professional sustenance elsewhere, notably in an invisible college of several sympathetic historians, especially John Heilbron, whom I first met when he heard me clattering away on an old manual typewriter in the archives of the American Philosophical Society; Paul Forman, to whom John introduced me; and Martin Sherwin, whom I first encountered in the Manuscripts Division of the Library of Congress and whom I noticed because he had jotted down in the registry book that his topic was Robert Oppenheimer. All were working on subjects complementary to my own. They took an interest in my project, as did I in theirs; John and Paul read drafts of chapters, and provided criticism and suggestions of indispensable value. Eric was particularly encouraging, too, listening to my ideas, giving critical readings to drafts of the manuscript, and bolstering my sometimes flagging resolve. And I had the good fortune to have in Ashbel Green at Alfred A. Knopf, an editor who was at once tough and seasoned but patient and forbearing.