Von Weissen Nächten und Roten Tagen. Kharkov, 1933.
1935
Encyclopadia of Sexual Knowledge. By Drs. A. Costler, A. Willy and others. Under the general editorship of Norman Haire, London, 1935.
1939
The Gladiators. Cape, London, 1939.
1945
The Yogi and the Commissar. Cape, London, 1945. (A kötetből csak a címadó esszé jelent meg magyarul.)
Twilight Bar. An escapade in four acts. Cape, London, 1945.
1948
The Challenge of our Time. A series essays; Marschall, London, 1948.
1949
Insight and Outlook. Macmillan, New York, 1949.
1955
The Trail of the Dinosaur and Other Essays. Collins, London, 1955.
1956
Reflections on Hanging. Gollanz, London, 1956.
1960
The Watershed. A Biography of Johannes Kepler. University Press of America, Lanham, 1960.
1961
Control of the Mind. 1961.
Hanged by the Neck. An exposure of capital punishment in England. (Author Arthur Koestler, C. H. Rolph.) Penguin, Harmondsworth, 1961.
1963
Suicide of a Nation? An enquiry into the state of Britain today… [By various authors] Edited by Arthur Koestler, Hutchinson, London, 1963.
1965
Arthur Koestler: Motivation: A Biased Review. = Studies in Psychology Presented to Ciryl Burt. Charlotte Banks and P. L. Brodhurst (eds). London 1965.
1968
Drinkers of Infinity. (Essays 1955–1967). Hutchinson, London, 1968.
1969
Beyond Reductionism. New perspectives in the life scienses. The Alpbach symposium. Arthur Koestler, J. R. Smythies (Editor). Hutchinson, London, 1969.
1972
The Roots of Coincidence. Hutchinson, London, 1972.
1973
The Lion and the Ostrich. (The eighth annual lecture under the ’Thank-offering to Britain Fund’) Oxford University Press, London, 1973.
The Challenge of Change. A Mass Experiment in Telepathy and Its Unexpected Outcome (with Sir Alister Hardy and Robert Harvie). Hutchinson, London, 1973.
1974
The Heel of Achilles. Essays 1968–1973. Hutchinson, London, 1974.
1976
Life after Death (with Arnold Joseph Toynbee). Weidenfeld and Nicolson, London, 1976.
1978
Janus: A Summing up. (Philosophical anthropology). Hutchinson, London, 1978.
1980
Bricks to Babel. Selected writing and comments. Hutchinson, London, 1980.
1984
Stranger in the Square. (With Cynthia Koestler, ed. Harold Harris.) Hutchinson, London, 1984.