You can't learn jazz from a book.
But this one was definitely worthwhile. I'm not a pianist and not a jazz musician, and I couldn't read through every page of this one, but I learned a lot that will help my playing and my listening.
You definitely need some music theory background to make sense of this book: he starts with some review of scales and chord construction, but I think you would get lost very quickly if you don't have existing familiarty with basics of scales and keys and the ability to read music on bass and treble clefs. I don't think the book works as a step-by-step guide to learning jazz, but it's full of useful information and strong examples.
The two strongest points of the book, for me, are:
1. Practical explanations about how jazz musicians think and talk about performing. For example, I thought the chapter on "comping" (jazz term for accompanying a singer or soloist) gave a lot insight into how to *think about* doing it, how to listen, how to comp on an unfamiliar tune, etc.
2. The listening guides! The book has an exhaustive appendix of great records of pianists as leaders or sideman/sidewomen, sometimes with examples of particular tunes and what to listen for. Even better, throughout the book, after Levine discusses a style or technique, he'll include footnotes of particular recordings to listen to for examples. If you love jazz, even if you never plan to play jazz piano, this forms an amazing listening guide to the world of jazz.
There's definitely no way to learn to appreciate or play jazz without extensive *listening* but this book is a great way to guide your ears and your brain about what to listen for and how to make sense of what you're hearing.