Nanoscale science, engineering, and technology, often referred to simply as “nanotechnology,†is the understanding, characterization, and control of matter at the scale of nanometers, the dimension of atoms and molecules. Advances in nanotechnology promise new materials and structures that are the basis of solutions, for example, for improving human health, optimizing available energy and water resources, supporting a vibrant economy, raising the standard of living, and increasing national security. Established in 2001, the National Nanotechnology Initiative (NNI) is a coordinated, multiagency effort with the mission to expedite the discovery, development, and deployment of nanoscale science and technology to serve the public good. This report is the latest triennial review of the NNI called for by the 21st Century Nanotechnology Research and Development Act of 2003. It examines and comments on the mechanisms in use by the NNI to advance focused areas of nanotechnology towards advanced development and commercialization and on the physical and human infrastructure needs for successful realization in the United States of the benefits of nanotechnology development.