This new volume provides a scientifically based exploration of the multifaceted world of endogenous opioids, including endorphins, enkephalins, dynorphins, endomorphins, and orphanin FQ/nociceptin, featuring a strong translational focus. Topics covered range from basic scientific investigations, to clinical applications, to investigations in areas such as oncology, childbirth, and disordered eating, to psychosocial contexts such as volunteering and positive emotions. One of the main goals of Endogenous Opioids is to provide recommendations for new directions in medical research and health policy that are rooted in sound scientific research.