This paper is a survey of the literature on boards of directors, with an emphasis on research done subsequent to the Hermalin and Weisbach (2003) survey. The two questions most asked about boards are what determines their makeup and what determines their actions? These questions are fundamentally intertwined, which complicates the study of boards due to the joint endogeneity of makeup and actions. A focus of this survey is on how the literature, theoretical as well as empirically, deals—or on occasions fails to deal—with this complication. We suggest that many studies of boards can best be interpreted as joint statements about both the director-selection process and the effect of board composition on board actions and firm performance.