It was a useful book and a quick read, but it REALLY hurts your credibility when it looks like it was written in Google Docs and you couldn’t be bothered to get an editor. It’s littered with errors: random symbols, repetitive words, spots where the author changed his mind on the direction of the sentence but forgot to backspace, paragraph breaks in the middle of a sentence, etc.
The idea behind the book is great, but it’s really hard to put much stock in recommendations made by someone who clearly didn’t even read it after writing.