By then, his reputation -- as demanding, unpredictable and surly -- was firmly established. He drove the Reykjavik officials batty, demanding a Mercedes-Benz with an automatic transmission, a swimming pool reserved for his exclusive use and a certain kind of chess table. He even prescribed the distance of the audience from the players.

At one point, while still in New York, he threatened to withdraw, complaining that the prize money was insufficient. Henry Kissinger, then President Nixon's national security director, called Fischer, urging him to go. James Slater, a London millionaire, doubled the purse to an unprecedented $250,000.

Fischer went to Reykjavik but continued to rile nearly everyone. He walked out of a game when he said the noise from the cameras was distracting. He arrived late at games and kept threatening to pull out.

The match transfixed television audiences around the world whose interest had been fanned by coverage that framed it in political terms. The Soviets had monopolized the world championships since World War II and regarded their domination of the game as evidence of the superiority of the socialist system. Fischer himself portrayed the historic contest as "the free world against the lying, cheating, hypocritical Russians. . . . They always suggest that the world's leaders should fight it out hand to hand. And that is the kind of thing we are doing . . . over the board."

There was no lack of drama in the contest. Both players blundered in the beginning, then fought furiously for the upper hand. At one point there were seven draws in a row.

Compared to that thrilling run of draws, the end, on Sept. 1, 1972, after two months of play, was anticlimactic. The players adjourned after five hours of play with Fischer clearly ahead. When it was time to resume play, Fischer sat alone at the table. Spassky, after studying the positions, phoned in his resignation, making Fischer the world champion.

Three years later, Fischer set another record: He became the first world champion to give up his title without losing. After failing to win a change in the rules by which the challenger must win, Fischer refused a challenge from Soviet grandmaster Anatoly Karpov, forcing the International Chess Federation to strip Fischer of his crown.

He avoided competition for two decades. By the time of his forfeiture, he was living in Pasadena, apparently with little means of support. He had joined the Pasadena-based Worldwide Church of God and reportedly gave it $61,000 of his Reykjavik prize money. Disillusioned, he left the church after Jesus Christ failed to return in 1975 as church founder Herbert W. Armstrong had promised.

Odd incidents popped up in the news, such as when Fischer was mistaken for a robber and jailed for two days. He accused Pasadena police of mistreating him and voiced his complaints in a 14-page pamphlet titled, "I Was Tortured in the Pasadena Jailhouse."

The Los Angeles Times reported in 1983 that he had cut himself off from most of his friends and had spent the previous decade living in cheap apartments, rundown hotels and the basement of a Pasadena home owned by a woman who appeared to be his last remaining friend.

He was lured from seclusion in 1992 by the offer of a $5-million rematch against Spassky in Yugoslavia. He proceeded to play despite a warning from the U.S. government that his participation would violate the economic sanctions imposed on the Milosevic regime. Asked about the possibility of a 10-year prison sentence and $250,000 fine if he played, Fischer stunned reporters at a news conference when he took out the cease-and-desist order from the U.S. Treasury and spat on it.

He won the match, collecting $3.3 million, but spent the next decade as an international vagrant, living in Germany, Hungary, the Philippines and Japan.

He made the news sporadically, often because of offensive remarks he made about Jews. He repeatedly claimed that he was the victim of a worldwide Jewish conspiracy, even though his mother was Jewish.

After the 9/11 attacks, he gave an interview to a Manila radio station in which he pronounced the destruction "wonderful" and said he wanted "to see the U.S. wiped out."

The U.S. revoked his passport, which led in 2004 to his arrest by Japanese authorities at Tokyo-Narita Airport. He spent eight months in a Japanese jail until Iceland offered him refuge. While he was a fugitive, his mother and sister died, and he was unable to attend their funerals. He has no known survivors.

Over the years, many theories were offered to explain his bizarre behavior. Garry Kasparov, the Russian grandmaster, speculated in the Washington Times in 1990 that Fischer had become "a prisoner of chess who got lost in its depths and could not find his bearings in the real world outside." Gudmundur Thorarinsson, who organized the 1972 Fischer-Spassky match, told the London Guardian in 2005 that Fischer occupied "a gray area between a genius and someone who is insane," adding that he did not think Fischer was mad "but he is not like most people."

What few commentators dispute is the impact he had on chess.

"Suddenly people . . . could turn professional. Prize monies went up. There was talk of founding a professional league. . . . Everybody was playing chess," David Edmonds, co-author of the book "Bobby Fischer Goes to War," told National Public Radio a few years ago. "And the very sad fact for chess, not just in America but in Britain and the West and actually all around the world, was that when Bobby Fischer failed to defend his title . . . in 1975, and became an almost complete recluse, his disappearance sucked out much of that boom in chess interest."