This United States Department of Defense publication, The Future Faces of Irregular Warfare: Great Power Competition in the 21st Century, is an edited volume of essays written by leading scholars and practitioners of irregular warfare and national security that presents a forward-leaning analysis of how irregular warfare (IW) between the U.S. and its competitors is likely to play out in several key theatres, such as the Indo-Pacific and the Baltics, and in particular issue sets, such as climate change, misinformation, economic coercion, and counterterrorism.