is now known about apoptosis in two short books, but 1 hope these volumes prove to be a guidepost, providing basic essential information on the biology and molecular mechanisms of apoptosis and its implications in some human diseases. As a significant am o unt of new information on apoptosis is emerging every week, it is unrealistic to expect that by the time these two books are published, all the articles will deliver up-to-date information. Nevertheless, 1 believe that the fundamentals of the apoptotic phenomenon are now firmly in place and are discussed at length in various chapters. Readers may find a small degree of overlap between some chapters. This was unavoidable since closely related areas of apoptosis research have been covered by more than one author.