It's very well-written and I recommend it, but just be aware that despite the "mastering" in the title it's not meant to be a deep-dive into Emacs. (The author

It's very well-written and I recommend it, but just be aware that despite the "mastering" in the title it's not meant to be a deep-dive into Emacs. (The author provides a lot of great additional content on his website if you want to go deeper into really mastering emacs.)