Nuclear forensics is the analysis of nuclear materials, devices, emissions, and signals to determine the origin and history of those nuclear materials and devices. At the request of the Secretary of Energy, and in consultation with the Secretary of Defense and the Secretary of Homeland Security, Restoring and Improving Nuclear Forensics to Support Attribution and Deterrence evaluates the U.S. government's nuclear forensics capabilities. A 2010 National Academies report, Nuclear Forensics: A Capability at Risk, characterized the precarious state of the national technical nuclear forensics (NTNF) program at that time: NTNF relied almost entirely on staff dedicated to and residual funding from other related programs. This summary report addresses the current state of U.S. NTNF capabilities relative to the National Academies evaluation in 2010 and recommends ways to improve the NTNF program through improvements in policy, operations, and research and development efforts.