How does anesthesia work? What are the risks? And how does the anesthetist know if you are really asleep? In this brisk survey, Aidan O’Donnell takes the reader on a tour of modern anesthetic practice. He begins by explaining general anesthesia: what it is, how it is produced, and how it differs from natural sleep and other forms of unconsciousness. He goes on to consider the main categories of anesthetic drugs, including anesthetic vapors, intravenous agents, muscle relaxants, and analgesics, together with explanations of how they work and what their purpose is. O’Donnell also examines the large role anesthetists play in specialized areas such as intensive care medicine, pain medicine, and childbirth.