This interview is concerned primarily with two periods in the life of Libby (1927-1940 and 1945-1954). After briefly discussing his early life and education, considerable attention is focused upon Libby's undergraduate, graduate, and post-graduate years (1927-1940) at the University of California, Berkeley. Major topics included are: growth of Berkeley science; Gilbert Lewis, Wendell Latimer and Ernest Lawrence; Libby's development of low-level counters; radiochemistry and discovery of isotopes; cross-disciplinary collaboration; Libby's interest in carbon-14; association with Samuel Ruben and Martin Kamen; hot atom chemistry and nuclear isomerism; Libby's experiences at Princeton during 1940-1941 (hot atom chemistry, development of heterogeneous catalysis and research on tritium) and his work on the chemistry of the diffusion process during WWII at Columbia University (Manhattan Project) are mentioned; the other major portion of the interview concentrates on Libby's development of the radiocarbon dating technique at the University of Chicago (1945-1954); special attention is devoted to: measurement of half-life of carbon-14; importance to Libby of Harold Urey; secrecy policy; collaboration with Aristid von Grosse, James Arnold and Ernest Anderson; improved counting technologies; first contacts with archaeologists; Viking Fund and cross-disciplinary collaboration; communicating ideas; Sunshine Project and fallout; AEC appointment; concluding remarks.