The emergence of nanotechnology as a major science and technology research topic has sparked substantial interest by the intelligence community. In particular the community is interested both in the potential for nanotechnology to assist intelligence operations and threats it could create. To explore these questions, the Intelligence Technology Innovation Center asked the National Research Council to conduct a number of activities to illustrate the potential for nanotechnology to address key intelligence community needs. The second of these was a workshop to explore how nanotechnology might enable advances in sensing and locating technology. This report presents a summary of that workshop. In includes an overview of security technologies, and discussions of systems, natural chemical/biological tags, passive chemical/biological tags, and radio/radar/optical tags.