On a regular basis, professionals, employers, community health leaders, and policy makers ask me, ‘‘What works best? What do I need to include in my program to make sure it works?’’ I enjoy sharing the complete answer, complete with an in-depth review of all the scientific principles, critiques of the rigors of our science, and limitations on our knowledge of application in various settings, but they usually want the simple 2-minute answer in lay terms . . . so I have finally come up with one. To be successful in helping people practice healthy life- styles, four things are needed: Awareness, Skills, Motivation, and Opportunity. This simple framework can guide the development and evaluation of any program.