Charles Tilly was an influential American sociologist and historian known for his work on social movements, political sociology, and historical sociology. He contributed significantly to the understanding of how collective action and social change occur, particularly in the context of Europe and North America. His research emphasized the importance of historical context in shaping social dynamics. Tilly is best known for his concepts of "contentious performances" and "repertoires of contention," which describe how groups express grievances and mobilize for change. His books, such as From Mobilization to Revolution and Social Movements, 1768-2004, have had a lasting impact on the fields of sociology and political science.