The redistricting process evokes major questions about representative democracy, fairness, and political accountability. This article covers the state of the field along three dimensions. First, it explains how redistricting bears on questions about racial and minority representation. Second, it examines how redistricting influences electoral competition, focusing on the alleged power of partisans and incumbents to draw maps that eliminate all but token opposition. Third and last, it discusses the issues surrounding the redistricting process itself and how various procedural reforms may influence political outcomes. Although significant progress has been made in understanding how different redistricting schemes create various biases in the electoral system, a review of the literature shows that major questions have not been resolved regarding the effects of redistricting on electoral competition, partisan polarization, and representation of communities of interest, especially minorities. Moreover, there is insufficient evidence from empirical research to justify any particular reform of the redistricting process. In addition to filling these gaps, future work might also broaden the scope of research to assess how redistricting affects other aspects of democracy, including political participation, efficacy, and trust.