Good sleep is essential for optimal health, yet a number of sleep disorders can interfere with consistent, restful sleep. From insomnia to sleep apnea and from narcolepsy to restless legs syndrome, these conditions can have an enormous impact on both the quantity and quality of an individual's sleep. This book is part of Greenwood's Inside Diseases and Disorders series. This series profiles a variety of physical and psychological conditions, distilling and consolidating vast collections of scientific knowledge into concise, readable volumes. A list of "Top 10" essential questions begins each book, providing quick-access answers to readers' most pressing concerns. The text follows a standardized, easily navigable structure, with each chapter exploring a particular facet of the topic. In addition to covering such basics as causes, signs and symptoms, diagnosis, and treatment options, books in this series delve into issues that are less commonly addressed but still critically important, such as effects on loved ones and caregivers. Case illustrations highlight key themes discussed in the book and are accompanied by insightful analyses and recommendations.