Alexander Alexandrovich Alekhine (October 31 [O.S. October 19] 1892 – March 24, 1946) was the fourth World Chess Champion. He is considered one of the greatest chess players ever.
By the age of twenty-two, he was already among the strongest chess players in the world. During the 1920s, he won most of the tournaments in which he played. In 1927, he became the fourth World Chess Champion by defeating Capablanca, widely considered invincible, in what would stand as the longest chess championship match held until 1985.
Alekhine's peak period was in the early 1930s, when he won almost every tournament he played, sometimes by huge margins. Afterward, his play declined, and he never won a top-class tournament after 1934. After Alekhine regained his world title in 1937, there were several new contenders, all of whom would have been serious challengers
Bobby Fischer, in a 1964 article, ranked Alekhine as one of the ten greatest players in history. Fischer, who was famous for the clarity of his play, wrote of Alekhine, "Alekhine has never been a hero of mine, and I've never cared for his style of play. There's nothing light or breezy about it; it worked for him, but it could scarcely work for anyone else. He played gigantic conceptions, full of outrageous and unprecedented ideas. ... [H]e had great imagination; he could see more deeply into a situation than any other player in chess history. ... It was in the most complicated positions that Alekhine found his grandest concepts SOURCE: http://en.wikipedia.org/wiki/Alexander_Alekhine