In the late 1980s, the relationship between physical activity or exercise and aging was one of great contemporary interest. On the one hand there was a growing elderly population in industrialized societies seeking an active rather than a passive retirement, while on the other hand there was much current interest in the benefits to health of physical activity. The first edition of this book, published in 1978, was acknowledged as a major review of the field. In the years since its publication, however, there were many advances in our knowledge, made evident by the fact that this second edition, originally published in 1987, contains over 50 percent more references, 1840 in total. The author shows how far we can improve our adaptation to the aging process through an increase in personal fitness. Aimed at gerontologists, physicians in geriatric medicine and sports medicine, as well as other interested in human performance (for example, the physiologist, physical educator, ergonomist and physiotherapist), the book would remain a standard reference work on this subject for many years.