Sleep is a fundamental state. We spend approximately one third of our lives asleep and our dedication to this activity is likely to reflect its profound significance in many areas of our functioning and well-being. Whereas sleep is often taken for granted and berated by those who are keen to achieve more in their waking hours; its disruption can be profound. Indeed, any new parent can testify to the draining effects of sleep loss; and those suffering from insomnia can often spend many desperate hours lying awake. Those who have been touched by horrific accidents caused by someone “falling asleep on the job” know of the sometimes catastrophic effects of its disruption.