There are a number of compelling reasons why sleep disorders should feature prominently in the training of paediatricians, child psychiatrists, and others involved in the care of children: (1) conservatively, 20 to 30% of children from infancy to adolescence have sleep problems which are considered significant by them or their parents; without effective treatment, these problems may persist for long periods; (2) sleep disturbance can harm a child's learning and behaviour, and, sometimes, physical development; (3) parenting and other aspects of family function can be seriously affected. In addition, the nature of the sleep disturbance, including its physiological aspects, might provide an insight into the mechanisms by which psychological disturbance is caused as a result of sleep loss or disruption.