As our sophistication in medicine and biology increases, it becomes clearer daily that no disease can be completely understood without reference to developmental processes, even in our aging population. The present collection of principles with selected supporting illustrations derived from molecular biology, biochemistry, genetics, pathology, and pediatrics provides a valuable overview of the often reciprocal impact of development upon disease. The style is so lucid that even the overburdened practitioner might find relaxation as well as education here. Even the layman (such as he who reads Scientific American) may find this treatise worthwhile. There are enough specifics to be rewarding in practical medicine among the seven chapters, which are entitled: "Nature of Developing Cells," "Tissues and Organ Reactions to Injury," "Neoplasia," "Genetic Diseases of Cells and Cellular Metabolism," "Metabolic, Nutritional and Chemical Injuries," "Infectious Injury," "Immune Injury and Hyperergic Tissue Reactions." The book is warmly recommended.