Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. Work within the intersecting disciplines at the core of nanotechnology innovation-including physical, life, and social sciences and engineering-has revealed the potential of engineered nanomaterials (ENMs) and nanoscale processes to collect and store energy, reinforce materials, sense contaminants, enable life-saving drugs, and shrink and accelerate computational devices in both incremental and paradigm-shifting ways. Further, nanotechnology has enabled development of entirely new materials and devices that can be exploited in each of these and countless other applications. The United States has set the pace for nanotechnology innovation worldwide with the National Nanotechnology Initiative (NNI). Launched in 2001 with eight agencies participating, the NNI today consists of the individual and cooperative nanotechnology-related activities of 20 Federal departments and independent agencies with a range of research and regulatory roles and responsibilities (see Table 1). Eleven of the participating agencies have R&D budgets that relate to nanotechnology, with the reported NNI budget representing the collective sum of these investments. Funding support for nanotechnology R&D stems directly from NNI agencies, not from any centralized NNI budget. As an interagency effort, the NNI informs and influences the Federal budget and planning processes through its participating agencies and through the National Science and Technology Council (NSTC).