The fıeld of behavioral economics combines psychology and economics to investigate how individuals actually behave as opposed to how they would behave if they were being perfectly rational (as in the sense of maximizing their utility). Although initial applications focused on consumer behavior, such as explaining why people failed to save adequately for retirement, the fıeld has moved increasingly into the area of explaining health behaviors as well as the design of lifestyle interventions, such as weight loss and smoking-cessation programs. This deep dive provides an overview of several important behavioral economics concepts of relevance to public health and health behavior change.