First published in 1950 by Dr. T. S. Harrison and his colleagues, this textbook quickly became a standard reference in internal medicine. Its success can be attributed to the meticulous editing, the expertise of its contributors, and the comprehensive coverage of medical topics. Over the years, Harrison Principios de Medicina Interna has evolved to keep pace with the rapid advancements in medical science, making it a trusted companion for medical students, residents, and practicing physicians worldwide.