Night shift-workers are often advised to take a prophylactic nap prior to starting the shift in order to improve alertness and performance. However, individuals often report difficulty initiating and maintaining sleep at that time of the day secondary to the alerting influence of the near-24 hour circadian rhythm (biological clock). A sleep-promoting medication may improve the quality of an evening nap and subsequent alertness and performance during a night shift. We will use Ramelteon, a melatonin agonist that is FDA approved for insomnia, in order to test the following hypotheses: