I got my copy this morning from Niggemann. Looks „practical“ and good!
I have to confess that I‘m no expert in these lines, neither from the white nor from the black side. So in the last hours I‘ve just cross-checked the book‘s lines superfically against some other resources ...
In the preface Khalifman characterizes his approach in this book as scientifically minimalistic: practical and riskless but always „on the bright side of the equality“. In fact the authors claim an overall += but of course in many positions it‘s not easy to decide if White‘s advantage is small, very small, microscopic or non-existent ...
Probably you want some lines, a few at least?!
A) Rubinstein: 4.Bb5 Nd4 5.0-0 c6!? 6.Bd3!? and after 6...Nxf3+ 7.Qxf3 d6 8.Be2 Be7 9.d3 0-0 10.Qg3 there are 4 pages of analysis, obviously improving on some recent games of Andreikin.
B) Symmetrical mainline: 4.Bb5 Bb4 5.0-0 0-0 6.Lxc6!? dxc6 7.d3 (from now on White‘s play is simple and harmless but straight forward!)
B1) 7...Bxc3 8.bxc3 Bg4 9.h3 Bxf3 10.Qxf3 Qd6 (as recommended by Ntirlis2016 and Johnson2018) and now after both 11.Qe2 (Nimzowitsch-Vajda 1926) and 11.Qe3 (Kasperian-Korchnoi 1952) the book offers an improvement.
B2) 7...Nd7 8.Ne2 (also 8.Bg5!?) Re8 9.Ng3 Nf8 and now 10.d4!? or 10.Be3 (along Firouzja-Yi 2016).
B3) 7...Bg4 8.h3 Bh5! 9.Kh2!? (with the idea 10.g4) is critical but += according to the authors
If you play the Spanish4Knights with White or Black you probably do not come around buying this book!?
tracke
Iv'e been following your discussion with interest and was wondering about the following combative Line:
Does Khalifman now go for the wild stuff involving an early g4 or does he simply 0-0 and follow up in typical Lopez style with Ne2,Ng3.