Assessment to Enhance Air Force and Department of Defense Prototyping for the New Defense Strategy is the summary of a workshop convened by the Air Force Studies Board of the National Academies' National Research Council in September 2013 to enhance Air Force and Department of Defense (DoD) prototyping for the new defense strategy. This workshop examined of a wide range of prototyping issues, including individual recommendations for a renewed prototype program, application of prototyping as a tool for technology/system development and sustainment (including annual funding), and positive and negative effects of a renewed program. Prototyping has historically been of great benefit to the Air Force and DoD in terms of risk reduction and concept demonstration prior to system development, advancing new technologies, workforce enhancement and skills continuity between major acquisitions, dissuasion of adversaries by demonstrating capabilities, maintaining technological surprise through classified technologies, and an overarching strategy of overall risk reduction during austere budget environments. Over the last two decades, however, many issues with prototyping have arisen.For example, the definitions and terminology associated with prototyping have been convoluted and budgets for prototyping have been used as offsets to remedy budget shortfalls. Additionally, prototyping has been done with no strategic intent or context, and both government and industry have misused prototyping as a key tool in the DoD and defense industrial base. Assessment to Enhance Air Force and Department of Defense Prototyping for the New Defense Strategy envisions a prototyping program that encourages innovation in new concepts and approaches and provides a means to assess and reduce risk before commitment to major new programs.