Technically there isn't any info here that isn't on the YNAB website, etc about the YNAB system. But the amount of RL people examples and the always so so friendly and approachable language makes this book amazing.
I read it as someone whose used the YNAB app on and off for years and it was well worth it. It would also be a great book for someone completely new to YNAB or budgeting.