Eszopiclone (Lunesta) is a new non-narcotic, non-benzodiazepine hypnotic agent which received FDA approval on December 15, 2004 for the treatment of acute and chronic insomnia. Multiple clinical trials have found that eszopiclone decreases sleep latency, improves sleep efficiency/maintenance and reduces wake time after sleep onset (WASO). Given its efficacy in promoting sleep onset and sleep maintenance and its excellent safety profile, this agent should be ideal as a pre-study sedative. The purpose of this study is to validate the use of Lunesta in improving the quality of overnight sleep studies.