Written primarily for 16-19-year-old students, this primer covers the anatomy and physiology of the key organ systems in the human body. It provides students with an overview of the anatomical details and physiological principles of the organ systems of the body and discusses the pathophysiology of common diseases that can affect them. It also considers how surgical approaches can be used to manage commonly presenting diseases of these systems. In addition, the primer explores surgery and anaesthesia both in a historical and contemporary context, examining how surgical and anaesthetic approaches have advanced over the centuries and how they continue to evolve to make surgery safer and more effective.