Diagnostic classifications of sleep and arousal disorders have been categorized in four major areas: disorders of initiating and maintaining sleep, disorders of excessive sleepiness, disorders of the sleep/wake pattern, and the parasomnias such as sleep walking, talking, and night errors. Another nomenclature classifies them into DIMS (disorders of initiating and maintaining sleep) and DOES (disorders of excessive somnolence). There are, in general, two theories of sleep. According to the restorative theory, wakefulness results in an internal state which is antithetical to continued wakefulness. Sleep results in the modification of that state (is restorative). According to the behavioral theory, sleep is a mode of behavioral adaptation to the environment--a behavioral state of diminished responsibility. Sleep stages identified from the observation of brain waves are divided into two divisions--REM and NonREM. During REM sleep dreams occur, and breathing and heart rate are irregular. NonREM sleep features stable breathing and regular heart beats. Sleep averages range from 16 hours a day for the neonate down to 8 hours for the adolescent. The most common types of problems in children (not always apparent) are as follows: snoring, waking and inability to go back to sleep, falling asleep, insufficient sleep, inability to go to sleep alone and waking too early. There are also psychiatric conditions and those that relate to organic condition. One final type of problem is drugs and alcohol. Sleep problems in children relate to reading. (PRA)