The use of human in vitro fertilization in the management of infertility is the outgrowth of years of laboratory observations on in vitro sperm-egg interaction. "The editors of this work have themselves contributed significantly to basic knowledge of the mammalian fertilization process. The observations of Don Wolf on sperm penetration, the block to polyspermy and, most recently, sperm hyperactivation in the monkey and human, Gregory Kopf's elucidation of the mechanisms of sperm activation during penetration and the reciprocal dialogue between sperm and egg, and Barry Bavister's definition of...