I still haven't read the book. I ordered it and it arrived today but I'm somewhat reluctant to actually read it, these sort of explanations aren't really my thing and I'm doubtful I'd actually enjoy it. Plus Lynch is ignoring it too. :s
It's a fun read and beautifully published. Even if it doesn't end up serving as canon its a nice way to be reacquainted with the universe of Twin Peaks. The audio book also has kyle and a few others voicing but I think given how it's published it's more suited as a printed piece.