This is not just another study of the effectiveness (or lack of effect) of sanctions. Instead it asks what conditions make it likely that countries will agree to join in imposing sanctions. Game theory, statistical analysis, regression analysis and other techniques are all laboriously mobilized to generate hypotheses that are then tested in four thorough case studies. It is these that will interest most readers. Where the author naturally sees evidence supporting her interpretations, others may lean toward giving more emphasis to circumstantial and contingent factors rather than the general explanations that apply to all cases.