Beginning with the Manhattan Project and continuing through the Cold War, the United States government constructed and operated a massive industrial complex to produce and test nuclear weapons and related technologies. When the Cold War ended, most of this complex was shut down permanently or placed on standby, and the United States government began a costly, long-term effort to clean up the materials, wastes, and environmental contamination resulting from its nuclear materials production. In 1989, Congress created the Office of Environmental Management (EM) within the Department of Energy (DOE) to manage this cleanup effort. Although EM has already made substantial progress, the scope of EM's future cleanup work is enormous. Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges provides advice to support the development of a cleanup technology roadmap for EM. The book identifies existing technology gaps and their priorities, strategic opportunities to leverage needed research and development programs with other organizations, needed core capabilities, and infrastructure at national laboratories and EM sites that should be maintained, all of which are necessary to accomplish EM's mission.