David John Moore Cornwell (19 October 1931 – 12 December 2020), better known by his pen name John le Carré was a British Irish author, best known for his espionage novels, many of which were successfully adapted for film or television. A "sophisticated, morally ambiguous writer",he is considered one of the greatest novelists of the postwar era. During the 1950s and 1960s, he worked for both the Security Service (MI5) and the Secret Intelligence Service (MI6). Near the end of his life, due to his strong disapproval of Brexit, he took out Irish citizenship, which was possible due to his having an Irish grandparent. Le Carré's third novel, The Spy Who Came in from the Cold (1963), became an international best-seller, was adapted as an award-winning film, and remains one of his best-known works. This success allowed him to leave MI6 to become a full-time author.[4] His novels which have been adapted for film or television include The Looking Glass War (1965), Tinker Tailor Soldier Spy (1974, 2011), Smiley's People (1979), The Little Drummer Girl (1983), The Night Manager (1993), The Tailor of Panama (1996), The Constant Gardener (2001), A Most Wanted Man (2008) and Our Kind of Traitor (2010). Philip Roth said that A Perfect Spy (1986) was "the best English novel since the war".