David Clark is a Senior Research Scientist at the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL). Since the mid 70s, Dr. Clark has been leading the development of the Internet; from 1981-1989 he acted as Chief Protocol Architect in this development, and chaired the Internet Activities Board. Recent activities include extensions to the Internet to support real-time traffic, explicit allocation of service, pricing and related economic issues, and policy issues surrounding local loop employment. New activities focus on the architecture of the Internet in the post-PC era. He is former chairman of the Computer Science and Telecommunications Board of the National Research Council.