The National Nanotechnology Initiative (NNI) was created in 2000 to focus and coordinate nanoscience and nanotechnology research and development (R&D) funded by several federal agencies. The purpose of NNI is to ensure that research leads to the responsible development and deployment of nanotechnology for economic benefit and national security. In the 21st Century Nanotechnology Research and Development Act (P.L. 108-153), Congress directed the National Research Council to review the program every three years to monitor its overall progress. This report provides the results of the first review, which addresses the economic impact of nanotechnology developments and provides a benchmark for comparing U.S. R&D efforts to efforts by foreign competitors. In addition, the report provides an assessment of the current status of responsible development and a discussion of the feasibility of molecular self-assembly.