Susan Olzak is Professor Emerita of Sociology at Stanford University. Her research has focused on two processes: the impact of competition on ethnic/racial conflict and on the effect of mobilization on social change and on policy and legislative outcomes. She published three books on race/ethnic mobilization and a number of articles on race/ethnic conflict, protest mobilization, social movements, and policy outcomes favored by social movements. Current work analyzes LGBTQ protest and political and business organizations in U.S cities and the impact of category spanning on the longevity and vitality of various types of social movement organizations, including terrorist organizations.