Historically, nutrient deficiencies have been of greater concern than dietary excess. However, along with the realization that deaths due to certain diseases are more prevalent in affluent countries came the conclusion that nutritional excess is of equal or in greater concern in many nations. Because immunologic reactions may play a role development of both cancer and atherosclerosis, better understanding of these interre- lated phenomena may lead to innovative ideas for control of these diseases. There has been considerable interest in the role various nutrients may play in regulating immunologic responses. This has been especially true as a possible mecha- nism by which fat modulates growth of tumors in animals. Likewise, deficiency or excess of a number of other individual nutrients have been linked to altered immune responses. This volume of Human Nutrition-A Comprehensive Treatise details the effects of a number of nutrients on immunity. The first chapter covers questionable and fraudu- lent claims linking nutrition and immunity. The next chapter examines several aspects of food allergy. Ensuing chapters focus on specific nutrients such as fat, cholesterol, arginine, vitamins C, A, and E, carotenoids, flavonoids, zinc, iron, copper, and sele- nium. There are two chapters on total energy intake affecting immune response, one examining protein-energy malnutrition and the other describing the effects of food restriction in otherwise healthy animals.