Les Nelson is a researcher at the Palo Alto Research Center working on innovations of socio-technical systems. His work considers how existing technologies get adapted to meet changing social practices. Les joined PARC in 2004, studying information sharing and collaboration support tools used in system engineering practices. His latest work on informal information sharing in the enterprise has lead to the development of keyhole tagging, an approach for selective information sharing in close collaborations. Les' involvement with Xerox goes back to 1995, where he was the first researcher hired into the FX Palo Alto Laboratory. His work in human-computer interaction lead to 2 products, 16 patents, and publications in social computing, mobile technology, and tangible user interfaces. Before FXPAL, Les worked for Lockheed R&D on a variety of projects in systems and software engineering for very large systems, software reengineering, and software reuse. Les started out in corporate life with the IBM Federal Systems Division as a software engineer on large scale, mission-critical, real-time systems. Les received an undergraduate degree in Mathematics and Computing from Trinity College, Hartford, CT, and a MS in Computer Science from the University of Wisconsin in Madison. His master's work was in mathematical programming and systems science.