There's a lot of good videos on this website that talk about GTO. However, I want a book or books to read in conjunction with watching the videos here to help me learn the fundamentals of GTO poker. I'll add that I'm halfway through a degree in mathematics so if a book is super math heavy and/or complex, it doesn't really bother me. I've bought the mathematics of poker and am waiting for delivery. I've also been looking into 'Applications of No-Limit holdem' and 'Expert Heads Up No Limit Hold’em volume 1 and 2' and I had a couple questions on them. Is 'Applications of No-Limit holdem' getting outdated or does it teach in such a way that the concepts can be applied to any game? And how much of 'Expert Heads Up No Limit Hold’em' is just applicable to heads up? Can I still use most of this book for 6-max cash or any other game I decide to play? Does it teach game theory in poker, or game theory in heads up poker? Finally, does anyone have any other suggestions of books to read?

Also will learning general game theory be valuable, considering time constraints? Like, should I learn the content taught in a standard Game Theory 101 course? Or will most of the stuff that is required be taught in the books?

And is there any other places I can learn the fundamentals of GTO?

Thanks :)