This dissertation integrates research on boards of directors with human and social capital perspectives to examine board appointments. A director's appointment to a board is in part due to the belief that the individual can contribute critical resources and monitoring to the organization. The ability of a director to provide these resources and monitoring depends on his or her level of human and social capital. This dissertation more fully integrates human and social capital perspectives into our understanding of board appointment events. From these theoretical underpinnings, a model is developed proposing that several human and social capital indicators, including educational level, expertise, director experience, and access to network structural holes, affect the likelihood of joining a new board, joining a prestigious board, and exiting a current board. I also consider a number of contextual- and individual-level variables that may potentially moderate the relationship between a director's human and social capital and director mobility. Through this dissertation, I make a number of contributions to the literatures on boards, board appointments, and human and social capital. First, I offer a more comprehensive perspective of the board appointment process by developing an individual-level perspective of board appointments. Second, I contribute to a more comprehensive understanding of the market for corporate directors. Third, I focus on several salient dimensions of director mobility. Fourth, I contribute to the growing literature on human and social capital at the board and director levels. Finally, I add to the growing literature on director selection.