This autobiography looks at the life and times of Victor Weisskopf, a scientist at the forefront of particle physics research who became one of the early advocates of nuclear responsibility. This book chronicles his life, set against the backdrop of one of history's most fertile periods of scientific endeavour. Coming of age as a physicist in pre-war Europe, Victor Weisskopf worked with such scientific greats as Niels Bohr and Wolfgang Pauli. He made seminal contributions to quantum electrodynamics, nuclear physics, and elementary particle physics, and he worked on the most important scientific project of the day - the Manhatten Project. The story of Weisskopf is truly international, moving from the Vienna of his childhood through Copenhagen, Zurich and on to Cambridge and Los Alamos. At each stopping point, he recreates the scientific ambience of the place, giving the reader an exciting sense of the close-knit community that existed among the brilliant scientists with whom he worked.