contents -- introduction -- 1 Competing Political Visions for Postwar Science Scientists and Science Legislation, 1945-1947 -- 2 Fear, Suspicion, and the Surveillance State The fas, huac, and the fbi, 1945-1948 -- 3 Individual Encounters I Scientists and aec Security, 1946-1948 -- 4 Individual Encounters II Scientists and huac, 1946-1948 -- 5 Negotiating Security The fas, the aec, and the jcae, 1947-1948 -- 6 Responses Scientists' Associations and Civil Liberties, 1948-1949 -- 7 Drawing the Line The aec, the National Academy of Sciences, and the aec Fellowship Program, 1948-1950 -- 8 Consequences The 1950s and Beyond -- conclusion -- notes.