Casino Royale is the first novel by the British author Ian Fleming. Published in 1953, it is the first James Bond book, and it paved the way for a further eleven novels and two short story collections by Fleming, followed by numerous continuation Bond novels by other authors.

The story concerns the British secret agent James Bond, gambling at the casino in Royale-les-Eaux to try to bankrupt Le Chiffre, the treasurer of a French union and a member of the Soviet secret service. Bond is supported in his endeavours by Vesper Lynd, a member of his own service, as well as Felix Leiter of the CIA and René Mathis of the French Deuxième Bureau. Fleming used his wartime experiences as a member of the Naval Intelligence Division, and the people he met during his work, to provide plot elements; the character of Bond also reflected many of Fleming's personal tastes. Fleming wrote the draft in early 1952 at his Goldeneye estate in Jamaica while awaiting his marriage. He was initially unsure whether the work was suitable for publication, but was assured by his friend, the novelist William Plomer, that the novel had promise.

Within the spy storyline, Casino Royale deals with themes of Britain's position in the world, particularly the relationship with the US in light of the defections to the Soviet Union of the British agents Guy Burgess and Donald Maclean. The book was given broadly positive reviews by critics at the time and sold out in less than a month after its UK release on 13 April 1953, although US sales upon release a year later were much slower.

Since publication Casino Royale has appeared as a comic strip in The Daily Express, and been adapted for the screen three times: a 1954 episode of the CBS television series Climax! with Barry Nelson as an American Bond, a 1967 film version with David Niven playing "Sir James Bond", and a 2006 film in the Eon Productions film series starring Daniel Craig as James Bond.

M, the Head of the British Secret Service, assigns James Bond, 007, to play against and bankrupt Le Chiffre, the paymaster for a SMERSH-controlled trade union, in a high-stakes baccarat game at the Royale-les-Eaux casino in northern France. As part of Bond's cover as a rich Jamaican playboy, M also assigns as his companion Vesper Lynd, personal assistant to the Head of Section S (Soviet Union). The CIA and the French Deuxième Bureau also send agents as observers. The game soon turns into an intense confrontation between Le Chiffre and Bond; Le Chiffre wins the first round, cleaning Bond out of his funds. As Bond contemplates the prospect of reporting his failure to M, the CIA agent, Felix Leiter, gives him an envelope of money and a note: "Marshall Aid. Thirty-two million francs. With the compliments of the USA." The game continues, despite the attempts of one of Le Chiffre's minders to kill Bond. Bond eventually wins, taking from Le Chiffre eighty million francs belonging to SMERSH.

Desperate to recover the money, Le Chiffre kidnaps Lynd and tortures Bond, threatening to kill them both if he does not get the money back. During the torture, a SMERSH assassin enters and kills Le Chiffre as punishment for losing the money. The agent does not kill Bond, saying that he has no orders to do so, but cuts a Cyrillic '?' for ????? (shpión, Russian for spy) into Bond's hand so that future SMERSH agents will be able to identify him as such.

Lynd visits Bond every day as he recuperates in hospital, and he gradually realises that he loves her; he even contemplates leaving the Secret Service to settle down with her. When he is released from hospital they spend time together at a quiet guest house and eventually become lovers. One day they see a mysterious man named Gettler tracking their movements, which greatly distresses Lynd. The following morning, Bond finds that she has committed suicide. She leaves behind a note explaining that she had been working as an unwilling double agent for the Soviet Ministry of Internal Affairs. SMERSH had kidnapped her lover, a Polish Royal Air Force pilot, who had revealed information about her under torture; SMERSH then used that information to blackmail her into helping them undermine Bond's mission, including her own faked kidnapping. She had tried to start a new life with Bond, but upon seeing Gettler—a SMERSH agent—she realised that she would never be free of her tormentors, and that staying with Bond would only put him in danger. Bond informs his service of Lynd's duplicity, coldly telling his contact, "The bitch is dead now."

Ian Fleming, born in 1908, was a son of Valentine Fleming, a wealthy banker and MP who died in action on the Western Front in May 1917. Educated at Eton, Sandhurst and, briefly, the universities of Munich and Geneva, Fleming moved through several jobs before he was recruited by Rear Admiral John Godfrey, the Director of Naval Intelligence, to become his personal assistant. Fleming joined the organisation full-time in August 1939, with the codename "17F", and worked for them throughout the war. Early in 1939 he began an affair with Ann O'Neill (née Charteris), who was married to the 3rd Baron O'Neill.

In 1942 Fleming attended an Anglo-American intelligence summit in Jamaica and, despite the constant heavy rain during his visit, he decided to live on the island once the war was over. His friend Ivar Bryce helped find a plot of land in Saint Mary Parish where, in 1945, Fleming had a house built, which he named Goldeneye. The name of the house and estate has many possible sources. Fleming mentioned both his wartime Operation Goldeneye and Carson McCullers' 1941 novel Reflections in a Golden Eye.

Upon Fleming's demobilisation in May 1945, he became the Foreign Manager in the Kemsley newspaper group, which at the time owned The Sunday Times. In this role he oversaw the paper's worldwide network of correspondents. His contract allowed him to take two months holiday every winter in Jamaica. In 1948 Charteris gave birth to Fleming's daughter, Mary, who was stillborn; Charteris and Fleming became engaged shortly in 1951.

Fleming had previously mentioned to friends that he wanted to write a spy novel, but it was not until early 1952, to distract himself from his forthcoming nuptials, that he began to write Casino Royale at his Goldeneye estate in Jamaica on 17 February; he typed out 2,000 words in the morning, directly from his own experiences and imagination, and finished work on the manuscript in March 1952.[a] It was a pattern he retained