Question: Who is older, Julian Barnes or Arthur Koestler?

<P0-S0>  Koestler was born in Budapest and, apart from his early school years, was educated in Austria. <P0-S1>  In 1931 Koestler joined the Communist Party of Germany until, disillusioned by Stalinism, he resigned in 1938. <P0-S2>  In 1940 he published his novel "Darkness at Noon", an anti-totalitarian work that gained him international fame. <P0-S3>  Over the next 43 years, from his residence in Britain, Koestler espoused many political causes, and wrote novels, memoirs, biographies and numerous essays. <P0-S4> Arthur Koestler, ( ; ] ; Hungarian: "Kösztler Artúr" ; 5 September 1905 – 1 March 1983) was a Hungarian-British author and journalist. <P0-S5>  In 1968 he was awarded the Sonning Prize "for [his] outstanding contribution to European culture" and in 1972 he was made a Commander of the Order of the British Empire (CBE). <P0-S6>  In 1976 he was diagnosed with Parkinson's disease and in 1979 with terminal leukaemia. <P0-S7>  In 1983 he and his wife committed suicide at their home in London. <SEP> <P1-S0>  Barnes won the Man Booker Prize for his book "The Sense of an Ending" (2011), and three of his earlier books had been shortlisted for the Booker Prize: "Flaubert's Parrot" (1984), "England, England" (1998), and "Arthur & George" (2005). <P1-S1> Julian Patrick Barnes (born 19 January 1946) is an English writer. <P1-S2>  He has also written crime fiction under the pseudonym Dan Kavanagh. <P1-S3>  In addition to novels, Barnes has published collections of essays and short stories. <SEP> <P2-S0> The Encyclopaedia of Sexual Knowledge, under the editorship of Dr. Norman Haire (1892–1952), is the first of a trilogy of sexual encyclopaedias by Arthur Koestler writing under the pen name of ‘Dr. A. Costler’. <P2-S1>  It is the English version, published by Koestler's cousin Francis Aldor in 1934, of the book "L'encyclopédie de la vie sexuelle" that Koestler in 1933 wrote, together with "A. Willy" (the pseudonym of his other cousin Willy Aldor) and the German Dr. Levy-Lenz. <P2-S2>  The second book is "Sexual Anomalies and Perversions, Physical and Psychological Development, Diagnoses and Treatment". <P2-S3>  The title of the third book is, in the original French edition of 1939, "L’Encyclopédie de la famille". <P2-S4>  This third book was subsequently translated into English and published under various titles and with changes to the structure and text of the original edition. <P2-S5>  The name of ‘Dr. Costler’ (or 'A. Coester') as the author or co-author of the book is omitted from later editions. <SEP> <P3-S0> Stranger on the Square is the third volume of Arthur Koestler's autobiography, published posthumously in 1984. <P3-S1>  It was co-authored with his wife Cynthia Koestler, née Jefferies, and includes autobiographical notes of her as well. <P3-S2>  The book was published by Hutchinson, London 1984, 242 pages including Index. <P3-S3>  ISBN  . <P3-S4>  It was edited by Harold Harris, who wrote the Introduction and Epilogue. <P3-S5>  He was Koestler's editor for many years. <P3-S6>  The book is illustrated with seven monochrome photographs plus a colour and another momochrome photograph on the dustcover.