Perhaps the single most important phenomenon of the 21st century is globalization. It is clearly redefining the international security environment, as well as many other aspects of human affairs. Yet, while analysts and scholars continue to study (and debate) its economic, social, and political effects, they have done comparatively little work concerning its impact on war, in particular the nature of war. In an effort to fill this gap, Lieutenant Colonel Antulio J. Echevarria II has written a monograph exploring the nature of war, and how it has changed as a result of globalization. He uses the Clausewitzian model of war's trinity (political guidance, chance, and enmity) as a framework for understanding the nature of war, a concept that has been only vaguely represented in defense literature. He then analyses the global war on terrorism via that framework. Lieutenant Colonel Echevarria concludes that the Clausewitzian trinity is alive and well.