Sleeping is an essential part of everyone's life yet it remains little understood is barely understood. You might think it's a relaxing recharge but in fact your brain is working harder at times overnight than when you're conscious in the day. Fresh insight into why and how we sleep has come from studying people with sleep disorders, especially sufferers of narcolepsy. The condition means that people fall asleep many times a day, completely out of the blue. A less known symptom is paralysing attacks, that can cause narcoleptics to fall to the ground - unable to move - several times a day. If a way can be found to ease their symptoms, it could open the way to helping any of us to control our sleep patterns and perhaps even to go without rest while staying alert. Gaynor Carr has been nodding off routinely since the age of seven. Her narcolepsy has made holding down a job impossible and made her question the idea of ever having children. Gary Beattie used to work in construction, un