Muttiah Muralitharan has decided to retire from Test Cricket after Galle Test against India, although he may continue to play in the ODIs after that.
He is the leading wicket taker in both Test Cricket and ODIs, and I would not put it past him to be the only person with more than 800 wickets in tests. He currently has 792, which could have been more given the time sat out over the rows about his bowling action.
He is responsible for one of the biggest changes in cricket law to do with the bowling arm in terms of how straight it could be. His arm is naturally crooked and following constant calls against him, the ICC showed that nearly all bowlers have the same flaw when bowling.
Best spinner ever? Well, a certain Mr. Warne might argue against that, but he is certainly the finest off spinner so far.