In the twelve years since _Early Man in the New World_ appeared, in 1950, a good deal of archaeological water has passed under the bridge—or over the land-bridge that led the first immigrants into the Americas. Because I had given most of these years to the founding and development of the Department of Theater Arts at U.C.L.A., I was in no position to revise and add to that book without the collaboration of an able and willing anthropologist, a man who had followed far more closely than I the new findings in American prehistory, and the new theories, or guesses, about their meanings. I was fortunate indeed to find such a man in Professor Joseph A. Hester, Jr., of the Department of Sociology and Anthropology, San Jose State College, California. To him must go the fullest credit for the updating and the correcting, too, of a twelve-year-old book. Through him, _Early Man in the New World_ is now able to present a great deal of information that was not in existence in 1950. Then, for example, the dating of wood and charcoal, bone, horn, and shell, through radiocarbon was hardly more than a gleam in the eye of Willard F. Libby. As I was reading page proof when he announced his first pre-Columbian date, I could mention this invaluable time clock only at the end of three chapters. A change, rather than an addition to the text, is the use of the word “Clovis” instead of “Generalized Folsom,” and “Eden” instead of “Yuma,” thus bringing our terminology in line with today’s practice. In its first form, the book came about almost by accident. During 1941 and 1942, my work in the Office of the Coordinator of Inter-American Affairs included the preparation of some educational films upon archaeological work in Mexico and South America. As a result I came to know and esteem the Director of the University Museum, George C. Vaillant. To my surprise and pleasure, when he learned of my interest in American archaeology, he proposed that we collaborate on a prehistory of the New World. When the war prevented active work together by taking him to Peru, I prepared what would have been the first two chapters of our book—the place of early man in the story of pre-Columbian America. Upon Vaillant’s untimely death, I decided to study the subject more intensively, to add material on the Great Ice Age and early man in the Old World, and to expand the two chapters into a book that I might dedicate to the man who had done so much for American archaeology in the twenty years of his work—George C. Vaillant.