Fibromyalgia (FM) is a prevalent, debilitating, and costly syndrome. Although the pathophysiology of FM is not yet well-understood, sleep disturbance is a prominent feature of most theories. Eszopiclone has been approved by the FDA for the treatment of insomnia, but has not been studied in the treatment of FMS. The purpose is to assess the efficacy of eszopiclone for the treatment of insomnia and other symptoms of fibromyalgia (FMS) in FMS patients. Participants will be randomly selected to receive eszopiclone or placebo. It is hypothesized that participants receiving eszopiclone will report greater improvement in total sleep time, sleep quality, pain, fatigue, physical functioning, and emotional distress than will those receiving placebo.