Aspen Policy Books is a series of annual publications on the United States’ most pressing foreign policy and national security issues. In 2017, the Aspen Strategy Group examined the future of the liberal world order. The papers in this volume outline the history and importance the system of institutions and normative values that have underpinned the international system since the end of WWII. They also highlight some of the key threats to this order that have emerged over the past several years and endeavor to provide practical recommendations for meeting these challenges.