Henry R. Nau's bestselling book, Perspectives on International Relations, is admired for its even-handed presentation of realism, liberalism, constructivism, and critical theory--and for expertly applying those perspectives in every chapter, training students to think critically about the world's most urgent issues. This hallmark of the book hasn't changed; it highlights different causal perspectives from various levels of analysis to illuminate historical and current controversies in world affairs. But the overall length of the book has. With significantly briefer and more focused chapters, students can better grasp the causal logic and strong explanatory power of each of the perspectives as they explore the roots of major world events and approaches to critical issues.