Garry Kimovich Kasparov (Russian: Garri Kimovich Kasparov, Russian pronunciation: ['garjI 'kjim@vjItc ka'spar@f]; born Garik Kimovich Weinstein, 13 April 1963) is a Russian, and formerly Soviet, chess grandmaster, former world chess champion, writer, and political activist, who many consider to be the greatest chess player of all time. From 1986 until his retirement in 2005, Kasparov was ranked world No. 1 for 225 out of 228 months. His peak rating of 2851, achieved in 1999, was the highest recorded until being surpassed by Magnus Carlsen in 2013. Kasparov also holds records for consecutive professional tournament victories (15) and Chess Oscars (11).
Losing the title and aftermath
The Kasparov-Kramnik match took place in London during the latter half of 2000. Kramnik had been a student of Kasparov's at the famous Botvinnik/Kasparov chess school in Russia, and had served on Kasparov's team for the 1995 match against Viswanathan Anand.  The better-prepared Kramnik won game 2 against Kasparov's Grunfeld Defence and achieved winning positions in Games 4 and 6, although Kasparov held the draw in both games. Kasparov made a critical error in Game 10 with the Nimzo-Indian Defence, which Kramnik exploited to win in 25 moves. As White, Kasparov could not crack the passive but solid Berlin Defence in the Ruy Lopez, and Kramnik successfully drew all his games as Black. Kramnik won the match 8 1/2 -6 1/2 . Kasparov became the first player to lose a world championship match without winning a game since Emanuel Lasker lost to Jose Raul Capablanca in 1921.  After losing the title, Kasparov won a series of major tournaments, and remained the top rated player in the world, ahead of both Kramnik and the FIDE World Champions. In 2001 he refused an invitation to the 2002 Dortmund Candidates Tournament for the Classical title, claiming his results had earned him a rematch with Kramnik.  Kasparov and Karpov played a four-game match with rapid time controls over two days in December 2002 in New York City. Karpov surprised the experts and emerged victoriously, winning two games and drawing one.  Due to Kasparov's continuing strong results, and status as world No. 1 in much of the public eye, he was included in the so-called "Prague Agreement", masterminded by Yasser Seirawan and intended to reunite the two World Championships. Kasparov was to play a match against the FIDE World Champion Ruslan Ponomariov in September 2003. But this match was called off after Ponomariov refused to sign his contract for it without reservation. In its place, there were plans for a match against Rustam Kasimdzhanov, winner of the FIDE World Chess Championship 2004, to be held in January 2005 in the United Arab Emirates. These also fell through due to lack of funding. Plans to hold the match in Turkey instead came too late. Kasparov announced in January 2005 that he was tired of waiting for FIDE to organize a match and so had decided to stop all efforts to regain the World Championship title.

Q: When did he lose the tittle?
A: 2000.
Who did he lose it to?
Kramnik
Kramnik