Robert James "Bobby" Fischer (March 9, 1943 – January 17, 2008) was an American chess Grandmaster and the eleventh World Chess Champion. Many consider him the greatest chess player of all time.

At age 13 Fischer won a "brilliancy" that became known as "The Game of the Century". Starting at age 14, Fischer played in eight United States Championships, winning each by at least a one-point margin. At age 15, Fischer became both the youngest grandmaster up to that time and the youngest candidate for the World Championship. At age 20, Fischer won the 1963–64 U.S. Championship with 11/11, the only perfect score in the history of the tournament. Fischer's My 60 Memorable Games (1969) remains a revered work in chess literature.

In 1970 and 1971, Fischer "dominated his contemporaries to an extent never seen before or since". During that period he won the 1970 Interzonal Tournament by a record 3½-point margin and won 20 consecutive games, including two unprecedented 6–0 sweeps in the Candidates Matches. In July 1971, he became the first official World Chess Federation (FIDE) number-one-ranked player, spending a total of 54 months at number one.

In 1972, he captured the World Chess Championship from Boris Spassky of the USSR in a match held in Reykjavík, Iceland, publicized as a Cold War confrontation which attracted more worldwide interest than any chess championship before or since. In 1975, Fischer refused to defend his title when an agreement could not be reached with FIDE over one of the conditions for the match. This allowed Soviet GM Anatoly Karpov, who had won the qualifying Candidates' cycle, to become the new world champion by default.

After this, Fischer became a recluse, disappearing from both competitive chess and the public eye until 1992, when he won an unofficial rematch against Spassky. It was held in Yugoslavia, which was under a United Nations embargo at the time. His participation led to a conflict with the U.S. government, which sought income tax on Fischer's match winnings, and ultimately issued a warrant for his arrest.

In the 1990s, Fischer patented a modified chess timing system that added a time increment after each move, now a standard practice in top tournament and match play. He also created a new variant of chess called Fischer Random Chess or Chess960.

During the 1990s and early 2000s, Fischer lived in Hungary, Germany, the Philippines, Japan, and Iceland, and made increasingly anti-American and anti-semitic remarks on various radio stations. Possibly as a result, his U.S. passport was revoked. Unaware of the revocation, Fischer traveled to Japan, where he was arrested by Japanese authorities and detained for more than eight months under threat of deportation. In March 2005, Iceland granted Fischer full citizenship, leading Japanese authorities to release him from prison. Fischer flew to Iceland, where he lived until his death on January 17, 2008.