This is where it all begins. Well, for me it was actually Melissa and Dallas Hartwig's first book, It Starts With Food, but that's more of a nutrition book than a cookbook so it's not on this list. The Whole30 book is an upgrade from that, with even better meal planning and cooking resources. No doubt that the official Whole30 Cookbook, which was released in 2016, is also a good one to keep in your kitchen. I'd like to get my hands on that one soon. Buy it here.
One of the best features of this book is that it has pairing and variations of ingredients that you can use. And if you're going Paleo, sometimes it can be hard to pick what ingredients are Paleo "compatible" that are available on your cupboard or available in a local grocery near you. The meals are easy to prepare and delicious. This book emphasizes on meal planning and preparation which helps you save a lot of time.