It is a Black repertoire based on the 3.Qa5 Scandi. I have not read the book, but I have read through his 1001 Endgames Exercises books … he breaks these downs better than anyone I have encountered in chess writing, for untalented idiots like me. Then again, mates in 1-3 moves in endgame scenarios (few pieces on the board) is about the simplest skill you can learn in chess … a far cry from the most complex skill, which I think is openings. The most criticism I have heard of this book is that there is not as much dense analysis or lines to train compared to other opening books, since he is more pedagogical and “wordy” in his writing. Should be a good thing for club players (hence the title).
I know nothing of books about the other openings you ask of.
To get the standard way folks derail your thread and don’t answer your specific question, here is the best advice for players rated less than 1900 …
1. Opening principles, not specific openings.
2. Tactics tactics tactics.
3. Basic endgames:
-Major pieces v a lone king.
-King and pawn endings (KP v K).
4. Analyze your own games, preferably with a stronger player or coach.
What book (not YT) recommendations do folks have for specific openings?
In particular, the Scandinavian, Vienna, and Czech-Pirc are of most interest to me.