This book gives you all the basic principles underlying solid walking bass lines. Comprehensive, easy to understand, with page after page of great transcriptions of the author's walking lines on the accompanying CD. The CD of NY professional jazz players can also be used as a swinging play-along CD. Endorsed by Eddie Gomez, Jimmy Haslip, John Goldsby, etc. The audio portion of this book is available for free download at shtml.
I use iRealPro on my gigs. But I'm always trying to figure out the way to play over chords. I've been using this book for a week and my playing has already improved. This book "bakes in" habits you can use when up against FakeBook chord progressions. A "must have".