I´m surprised, that this book gets so many views and posts, I´m more than disappointed.
I skimread the book due to "my" gruenfeld: nothing new under the sun, the presentation is superficial, strategic explanations: zero.
The book makes the impression of a work by a student under severe time trouble, i.e. copy and paste here and there, but no own thoughts. For example at p.25 he mentions the King´s Indian Attack "where White just plays g3, Bg2, 0-0 and d3 without looking at what Black is doing", but I found no single line, game or recommendation about it. An other example is the Breyer defence - just nine light annotated games or mere 13 pages about the proposed main defence.
Sorry, the whole concept could have worked twenty years ago, when no one had databases and the reader was glad to get an overview, today this kind of presentation looks somewhat funny.
All in all it´s really hard for me to see his target group, because his recommended openings are too ambitious for players under 1900, but the given lines are too light for stronger amateures.

- rather harsh comment, maybe my expectations were too high or I´m spoiled by quality chess and chess-stars books.