Presents cryptanalytic experiences of Brigadier John H.Tillman in India and England during the period 1920-1939, both as British Army officer and as War Office civilian cryptanalyst. Discusses details of some early Soviet transposition, additive and one-time pad systems and describes the roles of several other British military and civilian cryptanalysts.
https://www.governmentattic.org/28docs/Experiences1920-1939Tiltman.pdf