Nancy Jeschkes sleeping difficulties began on vacation a few summers ago. She blamed the noisy motel room, but her sleeping did not improve at home. Instead of her usual six to seven hours a night, the 37-year-old teacher slept just three or four. 'Id toss and turn for hours, then get up and pace,' she says. Nancy tried going to bed earlier, but the slightest noise, even her husbands breathing, disturbed her. She drank a glass of wine at bed-time and fell asleep immediately, but was awake two hours later. Her doctor prescribed a sleeping pill for two weeks. When she stopped taking the pills, though, she slept worse than ever. Most of us have the occasional short period of troubled sleep and then return to normal a few nights later. However, for one in six people insomnia is a continual problem. Now the Johns Hopkins Sleep Disorders Center in Baltimore has developed a nine-step treatment to help insomniacs cure themselves. It is based on the idea that by deliberately reducing time in bed and by modifying your waking activities you will be able to sleep more soundly. Psychologist Richard Alien, co-director of the Johns Hopkins Center, considers insomnia a 24-hour disorder. Thus, his treatment, which draws on research done by Arthur Spielman of the Sleep Disorders Center of the City College of New York, includes advice on daytime as well as bedtime behavior. What is the subject of the passage?