Kenneth Neal Waltz (/wɔːlts/; June 8, 1924 – May 12, 2013 was an American political scientist who was a member of the faculty at both the University of California, Berkeley and Columbia University and one of the most prominent scholars in the field of international relations. He was a veteran of both World War II and the Korean War. Waltz was a founder of neorealism, or structural realism, in international relations theory. Waltz's theories have been extensively debated within the field of international relations. In 1981, Waltz published a monograph arguing that the proliferation of nuclear weapons would increase the probability of international peace. The monograph was The Spread of Nuclear Weapons. Waltz developed this theory in later publications, including one that argued peace in the Middle East would be secured if Iran were to acquire nuclear capability. Leslie H. Gelb has considered Waltz one of the "giants" who helped define the field of international relations as an academic discipline. Columbia University colleague Robert Jervis has said of Waltz, "Almost everything he has written challenges the consensus that prevailed at the time" and "Even when you disagree, he moves your thinking ahead." Waltz's initial contribution to the field of International relations was his 1959 book, Man, the State, and War, which was based upon his dissertation of classified theories of the causes of war into three categories, or levels of analysis. Waltz refers to these levels of analysis as "images," and uses the writings of one or more classic political philosophers to outline the major points of each image. Each image is given two chapters: the first mainly uses the classical philosopher's writings to describe what that image says about the cause of war; the second usually consists of Waltz analyzing the strengths and weaknesses of that image. The first image argues that wars are often caused by the nature of particular statesmen and political leaders such as state leaders – example like Napoleon – or by human nature more generally. This is basically consistent with Classical Realism, which dominated the International Relations discipline at the time of Man, the State, and War but which Waltz would contest more fully in his next book, Theory of International Politics.