Do we age because our tissues become increasingly worn out? This book comprehensively dismisses this idea and provides a fresh perspective on the science and philosophy of aging. In this remarkably comprehensive work, the authors describe how lifespan is an intrinsic feature of each species and argue that aging has evolved as an adaptation for the benefit of the group. The book outlines the historical background and focuses on the different and often conflicting theories of aging. The authors propose that there is a 'lifetime clock' located in the central nervous system that signals via the blood and determines the rate of aging and timing of demise. Drawing on studies in multiple species, the text discusses the circulating factors that are involved in this process and suggests that the primary targets of the clock are stem cells whose rates of renewal dwindle with age, which in turn impacts most acutely on the immune system. As a consequence, the majority of age-related conditions, including disorders such as Alzheimer's disease, are ultimately triggered by infection. The book goes on to describe attempts over the centuries to defer aging, some of which presage current thinking, and review the biomedical and lifestyle options that are available to counter the onset of age-related disorders. Finally, the book concludes by discussing the profound ethical issues engendered by bids to develop new anti-aging treatments. Accessible to specialists and general readers alike, this book is a must-read for everyone with a serious interest in key questions surrounding mortality.
