I just released a new book "
Pro Tools 2020 - How it Works". It is the most visual, and with 1,160 pages, the most comprehensive book for Pro Tool
It is available as pdf, iBook, Kindle, and a 3-part printed book series on Amazon.
If you go for the pdf version, it is the least expensive option compared to other books, especially if you consider that you get the full content (including Pro Tools | Ultimate features that are clearly marked) and up to date to version 2020.11
Here is the link to the products page with many screenshots in case you are not familiar with my "Graphically Enhanced Manuals". I even make the full chapter 14 "Groups" available as a free book.
http://DIngDingMusic.com/ProTools/