The Developmental Biology of Reproduction documents the proceedings of the 33rd symposium of the Society for Developmental Biology. Reproductive Biology was selected as the main theme of the symposium. The symposium aimed to draw center attention on basic aspects of reproduction in both plants and animals in the hope of stimulating research that might provide the necessary foundation for effective, practical control of human reproduction. Five areas were selected for emphasis: the formation of eggs and sperm; the activation of the egg to develop into an embryo; the genetic and biochemical events underlying the early development of the embryo; the hormonal controls operating in the reproductive process; and the general control of implantation and growth of the mammalian embryo in the uterus. Thirteen reports were given by distinguished researchers in each of these areas. All biologists interested in a broad understanding of problems of reproduction will find this symposium interesting and important for their own work.