Health behavior lies at the core of any successful public health intervention. While we will examine the behavior of individual in depth in this course, we also recognize by way of the Ecological Model that individual behavior is encouraged or constrained by the behavior of families, social groups, communities, organizations and policy makers. We recognize that behavior change is not a simplistic process but requires an understanding of dimensions like frequency, complexity and cultural congruity. Such behavioral analysis is strengthened through the use of a toolkit of theoretical models and practical frameworks. While many of such models and frameworks exist, in this course we will review the Health Belief Model, Social Learning Theory, Theory of Reasoned Action, the Trans-Theoretical Model and the PRECEDE Framework. After building your behavioral analysis toolkit with these examples, you will see that actual behavior change program planning uses a combination of ideas and variables from different models, theories and frameworks. Ultimately we aim to encourage course participants to apply the idea that successful programs are theory based as they go about involving people in improving their health.