Hezbollah and Hamas are major players in Middle Eastern politics and have a growing involvement in global events. Despite their strikingly different beginnings, they share a common denominator-an adversary in Israel. Hezbollah and Hamas draws from primary interviews and documents coupled with a thorough review of current scholarship. This is a portrait of the organizations' roots, histories, ideologies, relationships, tactics, political outlooks, and futures. Joshua L. Gleis and Benedetta Berti present organization charts, maps, and a case study of the TriBorder Area in South America, which frequently serves as an operational center for terrorist groups. Recognizing that these two groups are increasingly relevant to U.S. national security, Gleis and Berti provide a comparative analysis of their histories and political missions that moves beyond reductionist portrayals of the organizations' military operations.