Aging has been defined as a syndrome of changes that are deleterious, progressive, universal and thus far irreversible. Aging damage occurs to molecules, to cells, and to organs. Over the past years, several theories have tried to explain the concept of Aging and Aging processes. This book attempts to explain to discuss in detail, first of all, the concept of life expectancy and maximum life span, then the various theories of Aging and the diseases associated with Aging. It is also discusses in detail the processes of slowing down Aging. This book will be of great importance to those who seek to understand Aging, the theories of Aging and the process of Aging.