Renowned scholar Bruce Bueno de Mesquita, who set the standard for the scientific approach to international relations and transformed the field, has returned with a reformulated fifth edition based on extensive reviewer feedback and guided by an emphasis on questions about the causes and consequences of war, peace, and world order. More than ever before, the strategic perspective in international relations is examined with complete clarity, precision, and accessibility.áWhat hasnÆt changed is Bueno de MesquitaÆs commitment to covering the fundamentals of IR. The foundational topics and examination are all there: the major theories of war, the domestic sources of international politics, an exploration of the democratic peace, the problems of terrorism, the role of foreign aid, democratization, international political economy, globalization, international organizations, international law, and the global environment. The first part of the book, ôFoundationsöoffers highly accessible coverage of key concepts, introducing students to different ways to think about the national interest and showing them how to use game theory and the strategic perspective/selectorate theory to better understand what happens in all aspects of international affairs. This section uses debate over North KoreaÆs nuclear weapons development as an ongoing example to build concepts and build confidence in the studentÆs how of basic modeling ideas. Also covered is a basic, intuitive introduction to game theory and other evidence and logic based tools for analyzing international relations. Part II, ôWar,ö next provides a more thorough evaluation of how domestic political incentives and the domestic institutions of governance shape choices about conflict initiation, escalation, and termination. It also surveys major theories of war and conflict, working through hypotheses derived from constructivism, neo-realism, liberalism and selectorate theory and evaluating them against the evidence to see what actually works and what doesnÆt.Chapters in Part III, ôPeace,ö build on the logic of collective action to help students see why it is so difficult to get national governments to do ôwhat is rightö even when they can agree on what is right, with chapters covering the effectiveness of international organizations and international law, as well as a thorough evaluation of environmental issues, human rights enforcement and the domestic and the international political economy of trade.áPart IV, ôWorld Orderö emphasizes efforts to promote the spread of democracy and economic prosperity. It also addresses how to understand and deal with terrorism. Whether examining terrorism, the spread of democracy or the alleviation of poverty, chapters in this section carefully examine which strategies work, which do not, and why. The Arab Spring provides a useful ongoing example of the strengths and weaknesses of foreign aid policy and military intervention policies. No other introductory text delivers such an easily-understood contemporary explanation of international politics, while truly enabling students to learn how to mobilize the key concepts and models themselvesùthus develop a new method for thinking about world affairs. More than ever before, Principles provides a comprehensive evaluation of all aspects of international affairs, systematically compares the accuracy of competing approaches to international relations, and walks students through the simple, intuitive models and games that capture the essence of the strategic, selectorate viewpoint.