First of all I have to say this is without a shadow of a doubt the best Najdorf "repertoire" book ever made. And for anyone who plays the Najdorf this is a must buy. However there are a few hiccups, such as the main system he recommends against 6. Bg5 line is a sideline called the Browne variation (6. Bg5 e6 7. Qf3 h6?!) (after Walter Browne), this imo was a mistake, and resulting endgames from this variation ends up with black being a pawn down in a oppositte coloured bishops endgame. This should with perfect play be a draw, however why should black go into a system where the best he can hope for is a draw? The other variation he recommends against 6. Bg5 is Nbd7 which is an upcoming popular variation that I believe in future will become a mainline, it's main exponent at top level chess is Giri. This is the system I'd recommend playing from the book, however I wish as his main recommendation he had chosen either the Poisoned Pawn variation of Gelfand's as these have been the main lines for decades and are still being played at top level chess. Therefore if you want good coverage on 6. Bg5 you'll have to look elsewhere. I'd recommend waiting for Cutting Edge 3 being released by Quality Chess in later 2011, this is dedicated solely to 6. Bg5 and should have all the main line variations init.
So in conclusion this is a must buy because of everything except the 6. Bg5 line.