More than two million medical students, doctors and other health professionals around the globe have owned a copy of Davidson’s Principles and Practice of Medicine since it was first published. Now in its 23rd Edition, this textbook describes the pathophysiology and clinical features of the most frequently encountered conditions in the major specialties of adult medicine and explains how to recognise, investigate, diagnose and manage them. Taking its origins from Sir Stanley Davidson’s much-admired lecture notes, Davidson’s has endured because it keeps pace with how modern medicine is taught and provides a wealth of information in an easy-to-read, concise and beautifully illustrated format. This book will serve readers everywhere as a core text that integrates medical science with clinical medicine, conveying key knowledge and practical advice in a highly accessible and readable format. The opening section describes the fundamentals of genetics, immunology, infectious diseases and population health, and discusses the core principles of clinical decision-making and good prescribing. A new second section on emergency and critical care medicine encompasses poisoning, envenomation and environmental medicine, and introduces a new chapter on acute medicine and critical illness. The third section covers the major medical specialties, each thoroughly revised and brought fully up to date. Two new chapters on maternal and adolescent/transition medicine complement the one on ageing and disease. A new chapter on medical ophthalmology has been included. Clinical Examination overviews summarise the main elements for each system and now feature in the biochemistry, nutrition and dermatology chapters. Presenting Problems sections provide a clear pathway for the assessment of and approach to the most common complaints in each specialty. Practice Point summaries detail the practical skills that medical students and junior doctors must acquire. Emergency boxes emphasise the core knowledge needed to manage acutely ill patients. In Old Age, In Pregnancy and In Adolescence boxes highlight differences in the practice of medicine in these patient groups, and illustrate the interfaces between medical, obstetric and paediatric services. The text is extensively illustrated, with over 1000 diagrams, clinical photographs, and radiology and pathology images. The global perspective is enhanced by an International Advisory Board of experts from 17 countries, and by authors from around the world.