The purpose of this study is to determine whether individuals with chronic insomnia disorder have a higher degree of physiologic arousal (resulting in their trouble sleeping) than good sleepers. The primary goal is to perform a rigorous quantitative assessment of physiologic hyper-arousal across two domains (autonomic nervous system and neurophysiology) in patients with chronic primary insomnia as compared to good sleepers matched for sex, age, body mass index (BMI) and race/ethnicity.