This paper surveys the empirical and theoretical literature on the mechanisms of corporate governance. We focus on the internal mechanisms of corporate governance (e.g., corporate board of directors) and their role in ameliorating various classes of agency problems arising from conflicts of interests between managers and equityholders, equityholders and creditors, and capital contributors and other stakeholders to the corporate firm. We also examine the substitution effect between internal mechanisms of corporate governance and external mechanisms, particularly markets for corporate control. Directions for future research are provided.