The chapter commences with an overview of the literature on executive roles, but then primarily addresses the central debate over whether top executives really have much influence on what happens to their organizations. On one side of the debate is much of the work in strategic management, which asserts that top executives can greatly affect—for good or for ill—the form and fate of their companies. On the other side, various schools within organizational theory—notably population ecology, contingency theory, and institutional theory—have argued that executives are greatly constrained by inertial, environmental, and normative forces. The chapter primarily elaborates on Hambrick and Finkelstein's introduction of the concept of “managerial discretion” as a theoretical lever for resolving this debate. The amount of managerial discretion, or latitude of action, that a given executive possesses arises from environmental, organizational, and individual factors. The chapter concludes with an overview of the literature on “the romance of leadership,” or the human tendency to believe that managers make a difference.