No doubt, there are many ways to practice "good" medicine, whatever this may be. Forty years ago the history, observation, and clinical examina- tion of a patient led to diagnosis and therapy. Since then, we have learned a great deal about the biochemical and physiologic processes in the human body and about the pathogenetic mechanisms by which they are disturbed and lead to disease. Today, the basis of clinical judgment and patient management is the understanding of pathogenetic mechanisms of disease. This concise and basic text of pathophysiology introduces the medical student to the basic pathophysiologic mechanisms. Each chapter begins with a short outline of the general physiologic and biochemical principles of an organ, a system, or a metabolic process; their possible derangements are described, with empha- sis on the more important and more frequently occurring diseases. Although the primary purpose is to convey a basic understanding of clinical medicine to first-year medical students, many students have used this book as a convenient reference up to and after graduation.