Affected individuals do not think of it as a medical disorder or are too embarrassed to see a doctor. However, many people suffer from the sleep disorder sexsomnia, where they engage in sexual activities while asleep in a sleepwalking-like state, without being able to remember it the next day. Others suffer from Kleine-Levin syndrome, which can lead to increased sexual desire following several days of sleep. In contrast, sex addicts experience an overwhelming obsession with sex that is ever-present and insatiable, day and night. What may sound like a funny anecdote is, for those affected, associated with the risk of sexual coercion, making it a serious medical issue that is, however, treatable. This book provides an overview of sexsomnia and sex addiction.