Gives a lot of information about insomnia and its causes. Also gives good tips to treatment, such as when to see a doctor, sleep questionnaires, and a sleep diary.

If you're wondering why you have insomnia, this site should be your first stop! It has charts of insomnia's symptoms, effects, types, mental causes, food & drug causes, sleep hygiene, sleep environment, medical & physical causes, and more. It also features information about a sleep questionnaire, how to keep a sleep diary, and information about sleep tests. What a wonderful resource!