This book is a concise review of medically important applications of Human Leukocyte Antigen (HLA) in medicine. It covers both basic knowledge of HLA and its main clinical applications in medical practice. Its two major aims are to assist students who are preparing for clinical immunology examinations, and to help people who want to understand more about this subject with brief and flexible sources of information. This book presents current, medically important information on the rapidly changing field of tissue typing and its relation with diseases. It includes updated information on such topics as tissue typing in medicine and transplant immunology.