James Prochaska is a psychologist best known for developing the Transtheoretical Model of Behavior Change. This model outlines the stages individuals go through when changing a behavior, such as quitting smoking or adopting a healthier lifestyle. His work emphasizes that change is a process, not an event, and that people can be at different stages of readiness to change. Prochaska's research has significantly influenced health promotion and intervention strategies. He has authored numerous articles and books, contributing to the fields of psychology and public health. His model is widely used in various settings, including healthcare, education, and counseling.