Since the late 1980s, the commercial gaming industry has grown rapidly on American Indian reservations. Today, more than 200 Indian nations own more than 400 gaming operations in 28 states, yielding revenues in 2006 of more than $25 billion. How did this come about and what are the effects on Indian nations and on non-Native communities? The organization of contemporary Indian gaming operations has its roots in tribal-state conflicts dating to the late 1970s. It is a governmental activity, carried out by tribal governments on the basis of the preexisting rights of Indian nations, although it has been substantially constrained by congressional legislation and federal court decisions. While gaming's effects are unevenly distributed across tribes, its political, economic, and social impacts on many Indian reservations have been significant and positive, and it has had positive economic effects on many non-Native communities as well, particularly in distressed areas. But our understanding of gaming's effects is hindered by a lack of comprehensive case studies of gaming-related tribal decision making and of gaming's effects on both Native and non-Native communities.