I basically learned how to play off of this book. It includes a CD with tracks so you can hear what it is referring to. Having no theory to start with, it took me ages to grasp some of the concepts, but I kept on coming back to it. I'd pick the book up for 15 minutes and try it out on my bass.
If you don't understand a section, just skip over it and come back later. It may make sense a month later when you randomly turn to that section again.
It teaches some music reading theory at the beginning, if that's your cup of tea. It teaches structures for major and minor chords and explains the various modes. It takes time to help translate the theory to how to actually create grooves. It also explains the different feels associated with different play styles and provides examples of how you would build grooves in each. Finally, it gives you care instructions and provides a buying guide.
That book, combined with the lessons at this site have been an incredible asset.
It's easily worth the buy, but you have to keep coming back to it. Don't expect to grasp everything in the book at once, especially if you don't come from a strong music theory background.