The last several years have been a landmark period in the ubiquitin field. The breadth of ubiquitin's roles in cell biology was first sketched, and the importance of ubiquitin-dependent proteolysis as a regulatory mechanism gained general acceptance. The many strands of work that led to this new perception are re- counted in this book. A consequence of this progress is that the field has grown dramatically since the first book on ubiquitin was published almost a decade ago M. Rechsteiner (ed. ), Ubiquitin, Plenum Press, 1988]. In this span, students of the cell cycle, transcription, signal...