This updated edition is an important book that should be in the libraries of all medical practitioners. Chapters 1 through 8 describe the development and function of the immune system in an organized and concise manner. However, the information that is more useful to the practitioner begins in the second section of the book, chapters 9 through 19, which concentrates on immunodeficiency disorders. Chapter 9, "Immunodeficiency Disorders: General Considerations," is a well-organized, comprehensive, and easily understandable guide to the most common questions related to immunodeficiency faced by the general pediatrician, such as How many upper respiratory tract infections are too many? What kinds of infections suggest an immunodeficiency? What basic laboratory studies can be used to screen for immunodeficiency? How do I interpret the results of multiple immunology tests, such as T-cell enumeration, or a low IgG4 level? If an immunodeficiency is found, what treatments and support groups are available for the patient? The remainder of the second section of the book explains the immunodeficiency disorders in detail, categorizing them by the part of the immune system that they affect. It also contains sections on the physiological immunodeficiency of immaturity, pediatric HIV (human immunodeficiency virus) infection, and other secondary immunodeficiencies. It is not surprising that the pediatric HIV section is already out of date, with just one paragraph devoted to protease inhibitors, and with a concluding statement expressing hope that the zidovudine study will provide important information on the prevention of perinatal transmission of HIV—information that is now widely implemented. The third and final section of the book, "Immunologic Aspects of Pediatric Illnesses," is also of great practical use to the pediatrician. This section reviews immunologic aspects of pediatric illness by category, including allergic, dermatologic, pulmonary, gastroenterological, rheumatic, renal, endocrinopathies, neurologic, infectious, and hematologic/oncologic illnesses. In addition, there are chapters on transplantation and infection in the compromised host.