Discusses some possible explanations for the "spiritual surge" and growing interest in the religious and spiritual (RS)-health connection. Then the authors offer a brief historical comment on the scientific study of the RS-health area, followed by a brief discussion of definitional and conceptual concerns. Scientific evidence that RS factors influence physical and mental health is examined. The authors conclude by discussing a few research issues that deserve attention and offering some brief observations and conjectures, including considerations for health professionals.