In this text, Gail Ulrich explains how the immune system functions, and explores the problems of immunodeficient conditions such as fungus infections, eczema, herpes and fibromyalgia. She surveys various mind-body and dietary influences on the immune system, and provides a complete immune-enhancing herbal pharmacopoeia, including echinacea, garlic, milk thistle, gingko, shitake, St John's Wart, licorice, nettles and valerian.