This book brings together an unprecedented number and range of contributions relating to sleep from different disciplines in one comprehensive volume. The contributors explore the history of sleep, both in literature and in science, and consider its sociological aspects. Sleep problems, sleep quality and the effects of drugs such as caffeine, nicotine and alcohol on sleep are discussed, together with the importance of sleep for daytime performance and the science of the human body clock. Medication and polysomnography (the measurement of sleep) are also explored, along with how sleep can be affected by medical and psychiatric conditions.