Introduction: When good sleep goes bad -- A tour of sleep -- Insomnia : bleary-eyed nights -- Obstructive sleep apnea : suffocating repeatedly in your sleep -- Restless legs syndrome : the agony of jittery drowsiness -- Hypersomnias : excessive sleepiness, daytime dysfunction -- Circadian-rhythm disorders : timing is everything -- Confusional arousals and the crush of severe morning sleep inertia -- Sleepwalking : the twilight state -- Abnormal sleepsex : unknowing cruel intimacy -- Sleep terrors : the night the ghost got scared -- Sleep paralysis : dreaded visits from the old hag -- Sleep-related binge eating : relentless loss of control -- REM sleep behavior disorder : bizarre and violent dream enactment -- Nocturnal dissociative disorders : the lost children as adults -- Sleep-talking : disruptive chatter, obscene shouting, and desdemona scenarios -- Parasomnia : shadows of obstructive sleep apnea -- Parasomnia potpourri : nocturnal groaning, exploding head syndrome, sleep-laughing ... and pets with parasomnias -- Bed partner's insomnia : sleeping with a snorer, leg-jerker, loud sleep-talker, or parasomniac.