Editors Laurie Brown and Lillian Hoddeson have brought together a distinctive collection of essays, discussions, and personal descriptions of the evolution of particle physics based on the presentations and discussions at the May 1980 International Symposium on the History of Particle Physics, held at Fermi National Accelerator Laboratory in Batavia, Illinois. This collection focuses primarily on the development of cosmic-ray physics and quantum field theory in the 1930s and 1940s, before the advent of the great postwar accelerators, and draws on research conducted in the United States, Italy, Japan, Great Britain, Germany, France, and the USSR.