This biography of one of the world's foremost demographers traces in addition to Ansley Coale's own life and work, the progress of worldwide demographic research in the 20th century. One chapter records the important work of his mentor, Frank Notestein, particularly on fertilty, and contraception's effect on it, as well as his founding of the Office of Population Research at Princeton, an institution vitally important in Ansley Coale's career. Coale's professional activities took him in such various directions as professor of economics at Princeton, studying population and economic development in low-income countries, research on the European Fertility Project, stabilizing analytical demography: including the study of stable populations, correcting bad data in the U.S. and other countries, and creating demographic models for mortality, fertility and marriage. As U.S. representative on the UN Population Commission he served as an advisor to Africa, Europe, Latin America and Asia and participated in the International Union for Scientific Study of Population. Coale directed the Office of Population Research between 1959 and 1973 and was Senior Research Demographer there until the late 1980s. One of his major focuses has been the social implications of atomic energy. He has received many honors and is the author of many articles and several books on population. Photos.