Early Infrared Research consists chiefly of correspondence and research material c.1931 - 48. Most of the correspondence was originally kept by Sutherland in 4 alphabetical box files and although it is not all 'scientific correspondence' in the strictest sense, it provides an interesting overall picture of Sutherland's career and research during this period. With the exception of Sutherland's Ph.D. thesis (B.1) there are no working papers or laboratory notes until the war time period. B.4 - B.29 contain working papers and reports by Sutherland and others documenting infrared investigations of hydrocarbons and penicillin. Item B.92 is almost the only surviving material from Sutherland's second period at the University of Michigan after the Second World War. cf. A.28 which contains carbon copies of 2 letters written immediately before his departure in 1956.