Just came across these three memoirs of intelligence in the East as part of a biblographic exercise. Thought people might be interested:

Brigadier General Wallscourt Helly Hutchinson Waters ‘Secret and Confidential,’ the experiences of a military attaché, (New York: Frederick A. Stokes,1926)
Latham Valentine Stewart Blacker On secret patrol in High Asia, with an introduction by Major-General Sir George Young-husband (London, J. Murray, 1922).
Wild, Max, translated from German by Anthony Haigh, Secret service on the Russian front, (London, G. Bles [1932])

All are in Cambridge Uni library
Greg