One in ten Americans suffers from chronic insomnia. Many receive sleeping pills and over-the-counter sleep aids, at an annual cost of over $40 billion. There are many different medicines, in what can seem like a bewildering variety.  Dr. Mendelson draws on his experience of 40 years doing research and treatment of insomnia to explain how sleeping pills work, as well as their benefits and drawbacks, and alternative non-medicine approaches.