I agree with AlanG. The coverage of the Classical line allows the class player to get his head in the door a bit to understand the important theory. Without Houska's book you'll find yourself outside with your nose stuck to the window instead.
It appears that chess engines, like Rybka, can sniff out some of the shortcomings in analysis very quickly. One has to wonder if the proof readers only eyeball the text when doing the checks before publishing. I guess "chess engine checks" are time consuming.
I'm going to go out on another limb here and state that I suspect Houska's work has been manipulated a bit in this section of her book -- and maybe not to her liking. For example, the text on p.74 clearly belongs in the note to 15.Re1 on page 89. Considering Houska's fine work placing text beside game scores earlier, why is this so obviously misplaced? I don't think this was her decision. I'm thinking the page 74 text was in the note to 15.Re1 in the first place but got changed by someone who was not aware this disturbance in the continuity of the book. Did the publisher interfere to the point of agitation here?
I've come across another issue in the note to 19.Bg3 in the stem game, p.90.
19.Qb3 Kh8 etc. does not lead to an equal position. Black loses a pawn with no compensation. I tried 19...Qd7 instead of 19...Kh8. Then gave White 20.Ne4 and followed with 21...b6 and I also tried 21...Rac8 but the positions were very difficult for Black. I thought they were like walking a tightrope over the precipice while White was watching to see if you fell -- very uncomfortable chess.
Then I went back in the game score to look for improvements. I was amazed to realize that 18...b6 instead of 18...Qc8!, in the stem game, gives Black better play. The Bg7-h6 move used in the 18...b6 variation has some tactical and positional strengths. At least it is an active piece, unlike in the 19.Qb3 lines.
You can realize these by letting your chess engine sniff around a bit. From Bh6 the B guards c1 so a White Ra1 can't play on the important c-file via Rac1. Also, the Black Q stays put and off the c-file leaving room for a Black R to be placed on c8 quickly. In additon, ...Bh6 gains a tempo on the Re3.
Many hands make light work so interested players can deny or verify some of this. Thanks.