This interview discusses the following subjects, among others: Zilsel emigrates from Austria to England in 1938, and then to the United States in 1939; parents unhappy in America in the 1940s; father's socialism in Austria. Undergraduate (physics) at College of Charleston, SC; to University of Wisconsin for graduate study; meets Gregory Breit; M.A. in mathematics; joins American Youth for Democracy (Young Communist League), and then the Communist Party in 1946. Follows Breit to Yale University in 1947 to complete doctorate. After Ph.D. at Yale completed, works with Fritz London at Duke University; original plans for instructorship at Yale abandoned by Breit when he discovered Zilsel could not get security clearance; comparison of Breit's and J. Robert Oppenheimer's attitudes. Southern aristocracy and social anti-Semitism in Charleston; London's isolation at Duke and his views on intellectual and cultural level there; Paul Lazarfeld. Zilsel expelled from Communist Party in 1948; London teaches one year in London and Zilsel goes to Colorado State. The House Un-American Activities Committee hearings; Zilsel's lawyer; suspension from teaching at University of Connecticut. Nathan Rosen and the physics department at Technion (Israel Institute of Technology) in Haifa; Zilsel, wife and children move to Haifa; joins physics department. Progression of Zilsel's political views; attitude toward Jews and Arabs in Israel. Moves to McMaster University in Canada, 1956; discussion of old dissertation topics (low energy neutron-proton scattering theory, Pais' f-field and its effect on scattering), and the switch to statistical mechanics and helium. Lecturer at Case Western Reserve University, 1958 (to avoid denaturalization); political activity there; reflects on his need to take extreme political positions. Conference in Vienna, 1987, "Die Vertriebene Vernunft;" pervasive sense of nostalgia and of having sold out. Reflections on father's suicide, Zilsel's own loyalty to principle, and the state of Israel. Detailed discussion of Fritz London; his personal style; Zilsel's contribution to his two-volume work on superconductivity and helium; joint paper with London on heat conductivity. London's lack of involvement in political activity, Breit's fear of it.