This book highlights religious faith from a positive psychology perspective, examining the relationship between religious faith and optimal psychological functioning. It takes a perspective of religious diversity that incorporates international and cross-cultural work. The empirical literature on the role of faith and cognition, faith and emotion, and faith and behaviour is addressed including how these topics relate to individuals’ mental health, well-being, strength, and resilience. Information on how these faith concepts are relevant to the broader context of relational functioning in families, friendships, and communities is also incorporated. Psychologists have traditionally focused on the treatment of mental illness from a perspective of repairing damaged habits, damaged drives, damaged childhoods, and damaged brains. In recent years, however, many psychological researchers and practitioners have attempted to re-focus the field away from the study of human weakness and damage toward the promotion of a positive psychology of well-being among individuals, families, and communities. One domain within the field of positive psychology is the study of religious faith as a human strength that has the potential to enhance individuals’ optimal existence and well-being.