After decades of systematic collection of data describing age-related changes in organisms, organs, tissues, cells and macromolecules, biogerontologists are now in a position to construct general principles of ageing and explore various possibilities of intervention using rational approaches. While not giving serious consideration to the claims made by charlatans, it cannot be ignored that several researchers are making genuine attempts to test and develop various means of intervention for the prevention and treatment of age-related diseases, for regaining the functional abilities and for prolonging the lifespan of experimental organisms. This book provides the most up-to-date information and a critical evaluation of a variety of approaches being tried for modulating aging and longevity, including dietary supplementation with antioxidants, vitamins and hormones, genetic engineering, life-style alterations, and hormesis through mild stress. The goal of research on ageing is not to increase human longevity regardless of the consequences, but to increase active longevity free from disability and functional dependence.