This authoritative handbook reviews the state of the science of self-knowledge, a key emerging area in psychology. Leading investigators describe innovative theory and research that is shedding new light on how -- and how accurately -- people perceive their own traits, thoughts, feelings, behavior, and relationships. Coverage encompasses the behavioral, mental, biological, and social structures that underlie self-knowledge; approaches to studying self-beliefs in specific domains; and the motives and biases that influence accuracy. The volume explores the personal and societal benefits of self-knowledge and also considers possible ways to enhance it.