In this article, we review the history of the social scientific study of leadership and the prevailing theories of leadership that enjoy empirical support. We demonstrate that the development of knowledge concerning leadership phenomena has been truly cumulative and that much is currently known about leadership. We identify the contributions of the trait, behavioral, contingency and neocharismatic paradigms and the results of empirical research on prevailing theories. Issues that warrant research in each of the paradigms and theories are described. Ten additional topics for further investigation are discussed and specific recommendations are made with regard to future research on each of these topics.