Career theory, like the phenomena it describes, has grown and developed over the past century. During that time, four main types of theory have emerged. This paper examines the contributions and limitations of each type, starting with the oldest, and identifies the most fundamental trends in the evolution of this theory. The key trend identified is a continuous shift from a relatively static to a relatively dynamic theory. The paper offers a synthesis of this literature, and concludes by suggesting what types of research and theoretical development are now needed if career theory is to continue to mature.