In recent years several different gene silencing phenomena have been discovered in plants. The book summarizes the most recent data on gene silencing phenomena such as trans-, inactivation, paramutation and co-suppression. Plant researchers will find this edition a valuable help in differentiating between a number of puzzling and partly contradictory gene silencing events. Those not familiar with plant molecular biology are introduced into the relevant methods and scientific models. In addition examples and models of gene silencing in flamentous fungi, Drosophila and mammalian systems are presented. By providing a comparative update on gene silencing effects in different eukaryotes, this book should stimulate communication among scientists working in diverse areas of eukaryotic gene regulation.