Non-fiction
1933 Brazilian Adventure – Exploring the Brazilian jungle in search of the lost Colonel Percy Fawcett.
1934 One's Company: A Journey to China in 1933 – Travels through the USSR, Manchuria and China. Later reissued as half of Travels in Tartary.
1936 News from Tartary: A Journey from Peking to Kashmir – Journey from Peking to Srinagar via Sinkiang. He was accompanied on this journey by Ella Maillart (Kini). Later reissued as half of Travels in Tartary.
1952 A Forgotten Journey – A diary Fleming kept during a journey through Russia and Manchuria in 1934. Reprinted as To Peking: A Forgotten Journey from Moscow to Manchuria (2009, ISBN 978-1-84511-996-6)
1953 Introduction to Seven Years in Tibet by Heinrich Harrer published by Rupert Hart-Davis, London
1955 Tibetan Marches – A translation from French of Caravane vers Bouddha by André Migot
1956 My Aunt's Rhinoceros: And Other Reflections — A collection of essays written (as "Strix") for The Spectator. Published by Rupert Hart-Davis, London.
1956 Noblesse Oblige: An Enquiry into the Identifiable Characteristics of the English Aristocracy — co-authored (as "Strix") with Alan S. C. Ross, Nancy Mitford, Evelyn Waugh, Christopher Sykes and John Betjeman. Illustrated by Osbert Lancaster.
1957 Invasion 1940 — an account of the planned Nazi invasion of Britain and British anti-invasion preparations of the Second World War. Published in the United States as Operation Sea Lion
1957 With the Guards to Mexico: And Other Excursions — A collection of essays written for The Spectator. Published by Rupert Hart-Davis, London.
1958 The Gower Street Poltergeist — A collection of essays written for The Spectator.
1959 The Siege at Peking — An account of the Boxer Rebellion and the European-led siege of the Imperial capital.
1961 Bayonets to Lhasa: The First Full Account of the British Invasion of Tibet in 1904
1961 Goodbye to the Bombay Bowler — A collection of essays written for The Spectator as 'Strix'.
1963 The Fate of Admiral Kolchak — a study of the White Army leader Admiral Kolchak who led the anti-Bolshevik movement in Siberia from November 1918 to January 1920.