physiologically mature gamete. Probably the most exciting area for research at the moment is the identification of the cytoplasmic mechanisms responsible for the meiotic arrest of oocytes and the factors responsible for initiating their maturation (Chapters 3 and 4). Less is known about the physiological changes in the male gamete in preparation for fertilization and this may be identified as a major area for future research. Although comparable data for the plant kingdom is presently restricted to studies on marine algae, new techniques for isolating angiosperm gametes (Chapters 1 and 17) promise rapid advances in this field. The second section looks at the events and molecules involved in gamete recognition, binding and fusion. One of the most controversial topics is when does sperm-egg fusion actually occur (Chapter 14).