Grandmaster Boris Avrukh, a noted Grunfeld expert, has delivered 600 pages across two volumes - the most ambitious project on this fascinating opening. Perhaps the expectation would be that this would be the "the truth" against which we could refer for many years into the future. However, as Graham Greene said "the truth has never been of any real value to any human being...", and Avrukh has delivered a pragmatic repertoire book - albeit a large one. In contrast, in 2004 Sakaev in How to Get the Edge Against the Gruenfeld did attempt to find the truth on the Grunfeld Exchange with 7 Bc4. His findings have bedevilled authors since, including as I will discuss, Avrukh.
How is the repertoire presented? Avrukh follows the tree format, and much of the analysis is clearly his own (I am in awe of the amount of work he has done). He is comprehensive - many seemingly rare and minor lines receive detailed coverage. For example, the variation 1.d4 Nf6 2 c4 g6 3 Nc3 d5 4 Bg5 Ne4 5 Nxe4, a line that has often annoyed me and which most other authors give little attention to, receives 7 pages!
While Avrukh is comprehensive in explaining the MOVES, there is much less discussion of the IDEAS, and also why he chose the lines for the repertoire that he did. I thought this was a strength of Yelena Dembo in Play the Grunfeld: Detailed coverage of this Kasparov favourite. She explained her choice of repertoire, and if she sometimes chose a second best line, she explained why. She also tried to explain the objectives and ideas of her repertoire. The latter was an even greater strength of Safest Grunfeld by Delchev and Agrest (D/A). This gives an indication of the target market for these books.
To the repertoire:
Modern Exchange with 8 Rb1: Avrukh goes into the complicated main line with 9...cxd4, exactly as I would expect. (Dembo chose the quite respectable 9...b6. D/A chose 9...Nc6 with Chiburdanidze's quirky 13...Bc7, with 9...b6 as the back up).
Modern Exchange with Be3: Avrukh goes into the Grunfeld endgames avoiding Nxd2, again expected. (Dembo went for the endgames allowing Nxd2, arguably one of her second best options, while D/A avoided the endgames. With line conclusions like "Black has no chances to win this position..." this was a worrying area of their repertoire. If you are going to play the Grunfeld, you MUST know the Grunfeld endgame.)
Classical Exchange with 7 Bc4: here Avrukh recommends two sidelines, showing Sakaev's enduring influence. The first is Koutley's 10...Bg4 11 f3 Bd7. The argument is that in comparison with Svidler's straightforward 10...Bd7, the Be3 can be loose. I never see it in any of the main lines. But my bigger question is that in some lines White gains a tempo by having played f3. Avrukh's second choice is 10...Qc7 11 Rc1 b6!? This was recognized by Hartson as "an important alternative" back in 1971 (!)in The Grünfeld Defence [Grunfeld Defense]. The problem is that Avrukh omits to address Sakeav's (admittedly small) recommendation for White. (Dembo goes for Simagin's 10...Na5, with Svidler's 10...Bd7 as the back up. D/A make a case for Shamkovich's 10...Qc7, with 10...Na5 as the back up.)
Russian System: Avrukh chooses the Semi-Smyslov with 7...Nc6 - in a "Grandmaster Guide" I would have expected him to present the more complicated Prinz or Hungarian, which are overdue a review. (Dembo and D/A also present the Semi-Smyslov as would be expected for their target market).
Bf4: standard, although I need to have a deeper look here (Dembo had her other second best option here).
5 Bg5: after 8 Qd2 Avrukh recommends 8...h6 immediately. I had thought this vulnerable to 9 Nh3-f4 so need to have a deeper look. (Dembo follows the mainline with 8...exd5, while D/H choose the very unusual 7...0-0!? potentially sacrificing a pawn.)
Fianchetto: Avrukh opts for the pragmatic c6 lines. I had always thought these a bit stodgy for Black - Karpov especially showed the pressure white can bring to bear. Avrukh presents some subtle move order changes to avoid the most passive positions. (Both Dembo and D/A opt for the more combative open variations).
To sum up: this book is aimed at a relatively high elo audience (2200 plus ?) where concrete moves are more important than ideas (the reader will already well understand middlegame concepts). That said, the book doesn't seek "the truth", and sometimes avoids the absolute mainlines for pragmatic alternatives. I really wonder how widely used - and therefore relevant - the Classical Exchange repertoire choices will be. Because of its sheer comprehensiveness this book is a MUST HAVE for any serious Grunfeld player, but surprisingly, any serious Grunfeld player may not adopt the entire repertoire. For lower Elo players Dembo's work is holding up surprisingly well. D/A is the best discussion of ideas but their repertoire choices are often unclear, and the reader can be left "hanging" at the end of lines.
Four stars might appear harsh, but this is not really a ground breaking work, rather just a very big and detailed repertoire book.