The opening pages are really repetitive, so consider starting from 'How to get the most out of this book'.
Note also there's a lot of sell of Wildfit, the programme run by the authors. Which is a bit annoying, but they gotta make a living. And this book does contain better health advice than most - health, not diet.
This is a gentle, informative, cheering you along, non-judgey, helpful sort of book. It has some new takes as well as presenting existing information in an easily understood way over the 9 weeks. It would work for those that are on the keto bandwagon as well as vegetarians, which is a true strength. It has an exit / rest of your life strategy.
Will it reverse type 2 diabetes? Sceptical, your genes are your genes. But it may well improve symptoms / delay the worst long-term problems associated with diabetes, which is what counts.
The recipes were not for me, but if you're a starting out cook used to eating 'convenience' food they may be of use.