In The Behavioral Origins of War, D. Scott Bennett and Allan C. Stam analyze systemic, binary, and individual factors in order to evaluate a wide variety of theories about the origins of war. Challenging the view that theories of war are nothing more than competing explanations for observed behavior, this expansive study incorporates variables from multiple theories and thus accounts for war's multiplicity of causes. While individual theories offer partial explanations for international conflict, only a valid set of theories can provide a complete explanation. Bennett and Stam's unconventional yet methodical approach opens the way for cumulative scientific progress in international relations. D. Scott Bennett is Professor of Political Science at the Pennsylvania State University. Allan C. Stam is Associate Professor in the Government Department at Dartmouth College.