The Paleo Solution by Robb Wolf
This is an excellent book if you want to understand the science underpinning the Paleo Diet. This book, alongside the Paleo Diet by Professor Loren Cordain, led to the current global paleo movement. It thoroughly examines all the facets of the Paleo diet.
The Primal Blueprint by Mark Sissons.
Mark Sisson's book also details the science behind the Paleo Diet but also looks at all the other lifestyle factors that influence your health. The Primal diet is broader than the Paleo diet in that it can include dairy products and some starches if they can be tolerated by the individual.
Gluten-fee Heaven and Free-from Heaven are two UK magazines that have lots of Paleo and free-from recipes and articles. They are published on alternate months.
Get the Glow by Madeleine Shaw
This is not a Paleo book but it doesn't matter at all. It has lots of very clear and delicious recipes that are all highly nutritious.
The Paleo Primer by Keris Marsden and Matt Whitmore.
This is hands down, my favourite Paleo book. It covers the science but also includes lots of practical advice on how to follow a Paleo lifestyle. It is a UK book and the recipes are easy to follow and delicious. There are lots of good paleo versions of traditional meals. If I had to buy only one book this would be it.
Paleo friendly blogs and websites