Twenty years ago, a group of investigators joined forces to propose a new conceptual paradigm based on a cognitive approach to motivation. This approach, referred to as goal systems theory, offered a broad perspective on behavioral phenomena and inspired research programs in diverse domains of psychological science. This volume collects the rich body of insights and findings that the goal systemic approach has yielded over the last two decades. Using the major cognitive architectures of goal systems, leading researchers from some of the world's most renowned universities push the envelopes of their respective fields to discover new psychological phenomena and relationships through applications. These include fundamental topics such as attitude-behavior relations, intrinsic motivation, consumer behavior, violent extremism, addiction, and interpersonal relations among others. In all those domains, applications of goal systemic analyses provide novel insights and guide real world interventions. Chapters in this volume present the authors' work in these varied domains of application thus offering concrete illustrations of the theory's reach and usefulness.