This book opens poignantly with a preface written by Vasquez following the funeral of his co-author, Senese. This joint work was the culmination of a decade's worth of collaboration exploring the value of the "scientific" approach to international affairs, of which they have both been leading exponents. The strengths of that approach, including its sharp focus, rigor, and sophistication, are fully on display. So, unfortunately, are its weaknesses: it is forbidding to anybody outside its methodological mindset, and although it may be systematic and statistical, it is not science. No reliable laws emerge from the work, just interesting propositions, few of which will appear to be strikingly original to those who are not dogmatic realists (the other intellectual tradition with which Vasquez and Senese most engage). The authors argue that wars are most likely to occur because of territorial claims; that if these claims lead to regular disputes over a period of time, the states involved are apt to end up in war; and that alliances make this more likely. They also note that these patterns were mostly in evidence between 1816 and 1945, after which things changed because of the Cold War and nuclear weapons -- although things may have reverted back to the previous pattern after 1990. Within these broad periods, individual cases are stripped of their context and nuance, and so much of the richness of international history, from the impact of ideology to domestic politics, is lost.