The defender

The defending champion is Viswanathan Anand, who won the World Chess Championship 2007 (a tournament with eight players) and defended the title in the World Chess Championship 2008 (a match against former champion Vladimir Kramnik).

The challenger
Further information: World Chess Championship 2006 and Chess World Cup 2007
The challenger to the title will be determined in a match between former FIDE World Champion Veselin Topalov and the winner of the Chess World Cup 2007, Gata Kamsky. Veselin Topalov has been given direct entry to a "Challenger Match" against Kamsky. The reason lies in the complications in reunifying the world title in 2006. The chess world title was split between 1993 and 2006. In early 2006, FIDE had already announced the conditions for the World Chess Championship 2007: an eight-player tournament which included FIDE World Champion Veselin Topalov, but not "Classical" World Champion Vladimir Kramnik. FIDE later organized a re-unification match between Kramnik and Topalov (the World Chess Championship 2006), with Kramnik to take Topalov's place in the 2007 tournament if he was to win the match. Kramnik did win the match and the reunified World Chess Championship, and so Topalov was excluded from the 2007 World Championship.In June 2007 FIDE announced that Topalov would be compensated by getting special privileges in the 2009 qualifying cycle: direct entry to a Challenger Match