To mobilize America’s intellectual resources to meet the security challenges of the post–9/11 world, US Secretary of Defense Robert M. Gates observed that “we must again embrace eggheads and ideas.” But the gap between national security policymakers and international relations scholars has become a chasm. In Cult of the Irrelevant, Michael Desch traces the history of the relationship between the Beltway and the Ivory Tower from World War I to the present day. Recounting key Golden Age academic strategists such as Thomas Schelling and Walt Rostow, Desch’s narrative shows that social science research became most oriented toward practical problem-solving during times of war and that scholars returned to less relevant work during peacetime. Social science disciplines like political science rewarded work that was methodologically sophisticated over scholarship that engaged with the messy realities of national security policy, and academic culture increasingly turned away from the job of solving real-world problems.