For almost half a century, international relations theorists of the behavioral school have been working toward the day when any comment about arms control, deterrence, or war itself can be properly, scientifically validated. In an effort to move this project forward, Bennett and Stam test the many theories against the available evidence, at least to the extent that it can be presented in a quantifiable form. They address the criticisms that point to the unreality of this approach, but rather than being put off by the paucity of such cases, their lack of comparability, and the range of variables involved, they offer an ever more refined analysis. They conclude that no single theory rules when it comes to making sense of interstate conflict; that the data work better with some theories than with others; and, fortunately, that qualitative, historical research can also help. They clearly still yearn for a degree of predictability but recognize the role of chance and the fact that policymakers often act in ways that no theory could ever predict. Whether qualitative researchers will reciprocate the pleas for partnership will depend on whether they can be persuaded that the great effort that goes into the quantitative work is worth the rather meager results.