Although general morphological features have been used to consistently identify the changes in cell ultrastructure occurring during apoptosis, as distinct from necrosis, important advances have been achieved more recently in the investigation of the cellular and molecular aspects of this process. This book brings together the latest international research on the complex subject of programmed cell death, and covers such areas as the biochemical mechanisms, introduction of DNA fragmentation, enetic regulation, and the importance of apoptosis in the immune system, particularly during T-cell development, and in cancer. The comparison of a number of common signal transduction pathways with those involved in cell growth highlights an important relationship between apoptosis and the control of cell proliferation.