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 new second section on emergency and critical care medicine introduces a significantly expanded and comprehensive account of the approaches to dealing with acute medical and critical illness. Two new chapters on maternal and adolescent/transition medicine complement the one on ageing and disease by addressing problems encountered at key stages of patients’ lives. A new chapter on medical ophthalmology has been included as a direct response to readers’ requests. The opening chapter has been completely rewritten with a new focus on the important principles of clinical decision-making or clinical reasoning. A new internal text design for this 23 rd Edition provides a simpler and clearer presentation of the various categories of text boxes.