The U.S. government supports a broad range of scientific and engineering research and development (R&D). Its purposes include addressing national defense, health, safety, the environment, and energy security; advancing knowledge generally; developing the U.S. scientific and engineering workforce; strengthening the capacity of U.S. institutions and firms to conduct cutting-edge scientific research and develop innovative technologies; and enhancing the competitiveness of the United States in the global economy. Most of the R&D funded by the federal government is performed in support of the unique missions of individual funding agencies. This book describes trends in federal R&D funding over the last 10 years, the funding and organization for selected multi-agency R&D initiatives and federally funded research and development centers.