I play bass and wanted a guide as to how to make up walking bass lines. This book is about making the bass player a jazz bassist. The book makes no assumptions about the starting level and begins at the start. It then progresses via stages to introduce more and more complex walking bass lines. This is really helpful as it shows how to "build the walk" from very basic (if you pardon the pun) to the most complex walks.
I should point out that this guide is primarily aimed at jazz style bass lines (which includes the blues, etc.) but these walking lines are adaptable to other genres. Ther are also a few very useful hints about playing, etc.
A useful aid is the CD which comes with the book. You can use it to hear the bass lines. I read music but the primary idea is to get the bassist to be able to build a line from the chords alone. So there are exercises to develop this.
Overall, if you want to get a good introduction to walking bass, this is a good guide. In particular, I did appreciate the step-by-step approach used by the author. It will not, of course, help you develop other styles directly, but will widen your bass horizons from simply playing the root note (base of the chord) repeatedly.