The new and updated edition of Health Behavior Change: Theories, Methods and Interventions, provides a complete understanding of health behavior change, from its theoretical building blocks to the practical challenges of developing and testing an intervention. Based on the latest evidence in the field, the authors present a theory-driven, scientific approach to understanding and changing health behaviors, examining the theories that explain health behavior, the techniques that most effectively change health behavior, and the methods and statistical approaches essential to generating the underpinning evidence. This approach is presented in the context of both health promoting behaviors such as healthy eating, and health risk behaviors such as smoking, and considers not only the role of individuals but also other important influences on health behavior including the environment, policy, and technology. Among other additions, the revised edition includes the following features: More classic and modern theories explained and critiqued Coverage of issues related to tackling COVID-19 through behavior change Consideration of the replicability crisis, its causes, impact and potential solutions Wider coverage of methods including different types of randomized trials, pilot studies, feasibility studies, consensus methods, N-of-1 studies and megastudies Expanded critical skills toolkit Fostering a critical perspective, the book includes features to enable readers to better evaluate evidence and Burning Issue Boxes to highlight relevant, topical issues in the field. It will be essential reading for students and researchers of health psychology, public health and social work, as well as any professional working in this important area, particularly those tasked with reducing the high proportion of individuals failing to meet national health behavior targets.