What does the Department of Defense hope to gain from the use of autonomous weapon systems (AWS)? This Letort Paper explores a diverse set of complex issues related to the developmental, operational, legal, and ethical aspects of AWS. It explores the recent history of the development and integration of autonomous and semi-autonomous systems into traditional military operations. It examines anticipated expansion of these roles in the near future as well as outlines international efforts to provide a context for the use of the systems by the United States. As these topics are well-documented in many sources, this Paper serves as a primer for current and future AWS operations to provide senior policymakers, decisionmakers, military leaders, and their respective staffs an overall appreciation of existing capabilities and the challenges, opportunities, and risks associated with the use of AWS across the range of military operations. Emphasis is added to missions and systems that include the use of deadly force.