Everyone has heard something about immunology if he's read anything about transplant operations. David Wilson here examines the rapid progress made in studying how the body distinguishes biological friend from foe. Wilson explains the details of antigens, antibodies and the basis of immune reactions. The bulk of the book traces the history of the science from pragmatic use of smallpox vaccinations through the discovery of germs, a long stagnation during 1910-50 to its present explosion under the impact of the discoveries of molecular biology. Current applications are varied from common allergies to possibilities of contraception by giving women immunity reactions to sperm. Recent research points to the idea that cancer is related to the failure of immunity mechanisms. Wilson makes it all clear, without reducing the content, to the lay reader. He does occasionally oversimplify on the broad questions of genetics and scientific method: but once immersed in his main subject, he is up-to-date, accurate, and lively.