This file contains a report on Thomson's visit to the University of Chicago (June 1942); the minutes of meetings of S1 Group, Washington (January-April 1942); a report of Thomson's interview at Columbia University with Professors Urey, Pegram and Dr. Szilard; notes of a meeting with Dr. Briggs and Dr. Breit; notes of a visit to Dr. Beams (November 1941); notes of a meeting at Columbia University with Drs Dunning, Booth and others (November 1941); notes of meetings with the American MAUD Committees (October 1941).