Fertilization provides in-depth reviews of individual research topics, while emphasizing key concepts and the significance of findings within other fields. The author identifies essential questions to be answered by future research. Fertilization broadly covers the many molecular and cellular events of animal fertilization and includes a section on unique problems and potential applications of fertilization research. Hardy's Fertilization reviews the biochemistry and cell and molecular biology of animal fertilization, with an overall emphasis on the nature and function of molecules that mediate this remarkable process. In Section I, experts in fertilization research review our current understanding of diverse fertilization events by exploring essential processes that range from gamete transport in the female to activation of embryonic development. General concepts and known molecular connections to processes in somatic tissues are emphasized. Where essential molecular detail is currently lacking, possible biochemical mechanisms are discussed, and plausible hypotheses are proposed in the form of testable models. In Section II, leading researchers review problems and questions that either are unique to gametes and fertilization or are exceptional incomparison to somatic cells or processes. In addition, practical aspects of fertilization research are presented, with an emphasis on the applications to biotechnology made possible by recent discoveries in fertilization molecular biology.