I've read a lot of poker books. Some meh, some great, and some atrocious. For the most part, I often don't think that Poker books are as effective as training site content in actually making a difference in EV. That being said, reading the right books can be instrumental in granting the theoretical background for getting much better at this game much faster. Below are all the books that will essentially teach you all you need to know about GTO poker.
*1. Applications of No Limit Holdem, Matthew Janda*
Decent book overall for introducing a theoretical approach to the game. This is what I would say is a great first book because it doesn't use too much jargon and gives you a general mathematical intuition for how GTO works. That being said, the bulk of the book is simply about thinking about bet sizes and calculating the appropriate frequencies of value to bluff ratios. There is some content on effective bluff selection but it simply isn't very explicit until you get to the very end of the book which covers hand reviews. Overall, the book is mostly theoretical.
*2. Mathematics of Poker, Billy Chen and Jerrod Ankenman*
Really theoretical. Vague in terms of how to actually apply the math covered in the book but still insightful and useful.
*3. Modern Poker Theory, Michael Acevedo*
Thank the heavens for this book. It not only covers the theory side but the entire book is grounded in highly practical implementable strategies that you can take straight to the table. It's backed by thousands of hours of solver study and teaches you the actual implementation of GTO principles along with the heuristics to apply them in game time. It's not some "frozen in time over the top highly abstract mathematical analysis" of how to calculate the optimal bet size and frequency.
*4. No Limit Holdem for Advanced Players, Matthew Janda*
If Applications was some annoying theory book that is super hard to apply, this would be the super practical book that more or less covers the same topics.
*5. Grinder's Manual, Peter Clarke*
Perfect balance between theoretical and practical. Peter is also a coach here on ROI. Everyone loves him for exactly said reason, backs up his theory with real examples. Going through From The Ground up along with the book will work great. The book also covers exploitative play.