Tim Richards' book "Exploring Jazz Piano 1" is probably the most thorough tome that I have ever worked through on this subject. Most jazz method books tacitly assume that you have already been seriously studying music for several years, so they skip over the elementary and delve headlong into the tricks of the trade (which can be daunting for those with a patchy knowledge).
This book makes no such assumption. If you don't have your basic theory and chops down when you begin this book, don't worry, you certainly will by the time you've finished it!
For those who have been playing classical and/or pop, etc for some time and know about intervals, inversions, scales, etc, it can be tempting to skip over all the stuff in the beginning of the book and dive straight into the meat of the course. However, I would still recommend that even those with a good foundation take the time to look through those early pages - you'll very probably find a few "Easter Eggs" that the author has tucked into the pages all over this book. Little morsels of wisdom and cool stuff that you might not be aware of abound.
Once you've gotten your feet wet, and begin looking deeper and deeper into this volume, you'll find a carefully crafted and logical progression of lessons that eases you smoothly into the jazz experience.
Many styles are covered, and the transcriptions are priceless! The function of the LH is also dealt with as being equal in importance to the role of the right. This is not just a collection of RH bebop licks to be regurgitated and thrown about like so much musical confetti, it is a serious curriculum that takes you to where you need to be with the least amount of pain possible - so that you can soon begin make your own music using the detailed principles meticulously outlined within.
If you really want to learn jazz piano, and you want to make sure that you know the subject inside-out "Exploring Jazz Piano 1" is one of the finest beginner's books I've ever encountered. Just buy it, you'll see!