Family background, education, and development of interest in physics; experience at Massachusetts Institute of Technology, absorbs prevailing political views. Postdoc position at Stanford University; relationship with Sidney Drell; fails to get tenure. Victor Weisskopf helps obtain position at University of California, Berkeley; Berkeley's environment. Participates in 1962 summer study as junior JASON; work on arms control issues with Matthew Sands; not invited back; negative implications of government consulting. Political transformation, 1966-1967; joins faculty peace group; letter to Physics Today refused publication on political grounds; SPD hearing; drafts proposal to amend American Physical Society constitution. Activism extends to concern with role of science in society; formation of Scientists and Engineers for Social and Political Action (SESPA); attack on JASON; research on power structures. Other activities: Hippocratic Oath for scientists; organizes free speech protests at Livermore; publication of Murray Gell-Mann papers; impact on career. Current involvements; views on crisis within physics.