The evolution of the science of health promotion in the past three decades has been quite remarkable. When I started my health promotion career in the late 1970s, there was really very little science to guide practitioners in the art of lifestyle behavior change. There was certainly a well-developed science of psychology, but most of that science was relevant to working with people with mental disabilities, or was highly theoretical. The field of health education was emerging, but most of the work in that area focused on understanding why people did and did not participate in health screenings and other medical regimes. The fields of nutrition and exercise science were well developed, but were just beginning to explore how to motivate people to change behaviors. The practices of stress management and organizational development were in full bloom, but the science base supporting them was still evolving, as was the science of addiction management. In speeches to health promotion professionals on health behavior change strategies during the decade of the 1980s, I often started presentations with the question: ‘‘What principles of behavior change guide your health promotion work?’’ The response was always the same: embarrassed silence. Occasionally someone would mention the Health Belief Model,1but would quickly admit to never really using it. Whatever science was emerging to support the art of lifestyle behavior change was in the purview of scientists, and had not filtered down to practitioners.