The preparation of Aging, Immunity, and Infection has been a "labor of labor. " When we began, there existed a huge literature-but manage­ able, we thought, given our years of experience in the area often referred to as immunogerontology. However, in the time that we have been at work, the new relevant literature has increased at a prodigious rate. The more we read and tried to assimilate, the farther we fell behind. In order to have any hope of completing a book on this rapidly evolving topic, we have been forced to become increasingly selective in covering new and re cent publications. We dare to hope that many read­ ers will find the book useful and only a few will dweIl on the inevitable inadequacies. We consider the book a work in progress, and welcome suggestions for future editions. Five chapters cover several aspects of infection and the decline of immunity with age. The first chapter "Human Aging: Present and Future," is devoted to demographics and theories of senescence. Chap­ ter 2 outlines the gradual breakdown of resistance to infection in the aged individual. Chapters 3 and 4 cover changes in innate and acquired immunity. The final chapter, "Nutrition, Longevity, and Integrity of the Immune System," discusses such provocative ideas as life-span extension and nutritional intervention for the delay of immunosenescence.