This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book describes a meta-analysis of the role of descriptive norms within the theory of planned behavior. It deals with the issue of belief elicitation and focuses on the effects of normative pressure within the theory of planned behavior—specifically in relation to breaking the speed limit. The book argues that the predictive validity of the theory of planned behavior could be enhanced with reference to goal theory. It considers a full spectrum of important developments that all enhance understanding of, and efforts to extend the theory of planned behavior. The book addresses important issues surrounding theoretical and practical approaches to problems in attitude-intention-behavior research. Historically attitudes had been assumed to be predictive of behavior, although the assumption was often held in the face of compelling evidence to the contrary.