Holy crap. I just realized you are 400 on Tactics Trainer. The last thing you need to be doing is finding a book on positional chess. Tactics are the language of chess. If you don't speak the language, you won't understand anything about it.
Hello. What Tactics Trainer level, do you think, would be sufficient to start with (simple) positional book?
I meant 1600 - 1350. That's bad enough!