This is a great primer for starters in understanding the blues pentatonic scale and developing fundamental blues licks and soloing ideas. The diagrams are clear and easy to follow and the lines are simple yet effective enough to get someone begin sounding realistic as a blues player. I'd recommend this book as a good way to get a clear and concise overview of the subject along with some good basic backing tracks to develop the lines and licks.
This is an excellent book by a fantastic author and is invaluable to all levels of blues musicians or for anyone who is contemplating starting to play blues guitar. I would highly recommend that you pick up a copy of this as a taster to the full version.