Understanding why we sleep remains one of the most enduring mysteries in science. While asleep, we cannot eat, mate, defend ourselves from predators or care for our young. Sleep is homeostatically regulated, i.e., sleep is driven by the duration and intensity of prior waking experience. However, the components, logic, and function of the sleep homeostat remains unclear. In this project, we will develop and apply an array of genetic and multi-omic strategies to reveal the molecular and circuit basis of the sleep homeostat using a simple animal model Drosophila. We also assess the functional impact on sleep-dependent lifespan and memory consolidation. Based on our discovery that neural mechanisms controlling the circadian regulation of sleep are widely conserved, we predict that core homeostatic mechanisms will similarly be widely conserved and thus, these studies should help address diseases that may result from impaired sleep including neurodegenerative and neuropsychiatric disorders.