Human beings have an evolved capacity for self-awareness, along with a propensity to focus primarily on their own welfare. This pervasive self-focus is reflected in thoughts, emotions, and actions whose underlying theme is the pursuit of self-interest. Although a focus on oneself has clear adaptive functions—such as physical preservation, decision making, planning, and self-regulation—this pervasive egoic mindset has psychological, interpersonal, and societal costs. In an increasingly crowded and interdependent world, there is a pressing need for the investigation of alternatives to a “me and mine first” mindset. For centuries, many philosophers, scientists, spiritual leaders, and social activists have advocated a “hypo-egoic” way of being, a psychological mindset characterized by less self-preoccupation in favor of a more inclusive, “we first” mode of functioning. In recent years, investigation of a variety of topics under the umbrella of hypo-egoicism has emerged in psychology, cognitive science, neuroscience, and philosophy as researchers have investigated both the features of hypo-egoic states and the psychological experiences that arise when self-focused processing is reduced, such as flow, equanimity, mindfulness, compassion, and mystical states. Bringing together current scholarship and science from multiple fields, theOxford Handbook of Hypo-egoic Phenomenaprovides an authoritative overview of theory, research, and applications concerning psychological states that involve diminished self-preoccupation and self-interest. TheHandbookalso reveals the widespread implications of such hypo-egoic functioning for personal well-being, optimal behavior regulation, interpersonal relationships, and prosocial and virtuous behavior.