'Operational Research. Recollections of problems studied, 1940-45', 'Brassey's Annual', 1953 Includes: invitation to write article, and corespondence with editor, Adam HG Thursfield, December 1951-September 1953; Correspondence re security clearance for material in article, 1953; Letter from Leonard E Bayliss with comments on Blackett's article and a copy of Bayliss's paper 'The origins of operational research in the army, October 1945', August 1953; Offprints of Blackett's article as published. Correspondents include: Basil Dickins, Rear-Admiral Henry Thursfield, 1953