Over the course of more than four decades the International Crisis Behavior (ICB) Project, a major and ongoing data-gathering enterprise in the social sciences, has compiled data that continues to be accessed heavily in scholarship on conflict processes. ICB holdings consist of full-length qualitative case studies, along with an expanding range of quantitative data sets. Founded in 1975, the ICB Project is among the most visible and influential within the discipline of International Relations (IR). A wide range of studies based either primarily or in part on the ICB’s concepts and data have accumulated and cover subjects that include the causes, processes, and consequences of crises. The breadth of ICB’s contribution has expanded over time to go beyond a purely state-centric approach to include crisis-related activities of transnational actors across a range of categories. ICB also offers depth through, for example, potential resolution of contemporary debates about mediation in crises on the basis of nuanced findings about long- versus short-term impact with regard to conflict resolution.