From the preface: "Sleep is a vital health behavior, and lack of sleep is reliably and prospectively linked with a host of adverse mental and physical health outcomes, including an increased risk of depression, suicide, accidents and injuries, cardiovascular morbidity, and mortality. Research has shown that sleep problems are prevalent in military populations— particularly among servicemembers who have deployed to combat operations in Iraq and Afghanistan, which is perhaps not surprising, given that sleep problems are a common reaction to stress. Research further suggests that, for many servicemembers, sleep disturbances persist for months or even years after deployments have ended. Thus, it is critical to understand the individual- and system-level factors that contribute to the onset, persistence, and exacerbation of sleep problems, as well as the downstream consequences for servicemembers’ mental and physical health and operational readiness. However, no study to date has comprehensively examined the types of sleep problems servicemembers are experiencing, the programs available to servicemembers to promote healthy sleep and treat sleep disorders, or the policy-level factors that may contribute to servicemembers’ sleep health across the deployment cycle and specifically in the post-deployment period, when sleep problems may have lasting implications for servicemember resilience."