Deals mainly with DuBridge's professional affiliations starting before World War II as member of National Research Council (NRC). War work at Massachusetts Institute of Technology Radiation Lab and relations with other groups, e.g., at the British Telecommunication Research Establishment (TRE). President of California Institute of Technology after Robert Millikan. Relationship with military. Establishment and chairmanship of President's Science Advisory Committee (PSAC); affiliations with PSAC and other organizations; PSAC's impact on science policy.