In October of 1992, the Harvard Center for Population and Development Studies sponsored the Roger Revelle Memorial Symposium on Population and Environment. Two dozen eminent scientists—all friends, colleagues, or students of Roger Revelle—presented papers in a broad range of disciplines that reflect the remarkable scope of Revelle’s professional and academic contributions during his lifetime. This volume is a selection of the symposium papers.A memoir of Revelle’s exposure to poverty in Pakistan, igniting his interest in the contribution that science could make to improving the lives of people in developing countries, serves as a moving introduction to the volume. This book stands as an enduring memorial to Roger Revelle’s lifelong concern that scientific developments contribute to comfortable, civilized survival in all countries of this increasingly crowded world.