This volume is a product of the efforts of the Institute for National Strategic Studies Spacepower Theory Project Team, which was tasked by the Department of Defense to create a theoretical framework for examining spacepower and its relationship to the achievement of national objectives. The team was charged with considering the space domain in a broad and holistic way, incorporating a wide range of perspectives from U.S. and international space actors engaged in scientific, commercial, intelligence, and military enterprises. This collection of papers commissioned by the team serves as a starting point for continued discourse on ways to extend, modify, refine, and integrate a broad range of viewpoints about human-initiated space activity, its relationship to our globalized society, and its economic, political, and security interactions. It will equip practitioners, scholars, students, and citizens with the historical background and conceptual framework to navigate through and assess the challenges and opportunities of an increasingly complex space environment.