The Control of Fertility is concerned with the experimental control of fertility as a specific biological problem. It is, first of all, an attempt to summarize a collection of data hitherto either partially or not at all presented. Secondly, it attempts to indicate those avenues which hold promise for future investigation. Finally, it attempts an assessment of the implications of understandings and ignorances. The book opens with an account of the sequence of processes essential to successful sexual reproduction in mammals. This is followed by separate chapters on approaches to the inhibition of spermatogenesis, ovulation, fertilization, and free ovum development. Subsequent chapters deal with blastocyst development and implantation, biological activities of compounds affecting fertility, fertility control in men and women, the inhibition of ovulation, biological properties of ovulation inhibitors in human subjects, and effectiveness and acceptability of contraception.