Insomnia, narcolepsy, night terrors, apnea, and sleepwalking are just a sampling of conditions afflicting sufferers who cannot sleep--and their experiences in trying are the stuff of nightmares. Demoniac hallucinations frighten people into paralysis. Restless legs rock both the sleepless and their sleeping partners with unpredictable and uncontrollable kicking. Out-of-sync circadian rhythms confuse the natural body clock's days and nights. Leschziner explores the many biological and psychological factors that allow us to find the rest necessary to maintain our health--and also improve our cognitive abilities and overall happiness.