Does religious faith influence health? Are religious practices associated with altered risks for morbidity or mortality? Do religious or spiritual individuals tend to enjoy better well-being or mental health across the lifespan? Does spiritual or religious involvement change the way individuals adapt to the demands of chronic illness? This volume brings together some of the leading investigators who have explored these intriguing questions. Though research is in its early phases, the chapters that follow review some of what we have learned and begin to trace the outlines of the many mysteries that remain.