Also available in paperback at this LINK
I decided to write this book because, almost always, in the ones I have bought over the years, let's say on the same "style," I never found an explanation of what was being offered. I could limit myself, therefore, to learning bass phrases, fills, grooves, without really understanding the meaning. Why were certain notes being played? Why were certain rhythmic elements working beautifully? On what chords were the bass lines "thought"? What scales or arpeggios, or substitutions, were being used and why? 
These, each time, were just a few of the many questions I asked myself after "parroting" the various examples offered.
Another thing, in my opinion instead fundamental, in all the books I bought, there were audio examples, but no backing tracks without bass guitar in order to play and study in the best way.
As with almost all my other instructional books then I thought, "Why not write one, exactly as I wished the ones I was buying years ago had been?" The title is a bit generic, because in reality not only Funk is covered, but also many similar styles of music from various different eras, and, in addition, many bass lines take inspiration from the greatest bass players in the history of these musical genres. A few examples: Francis "Rocco" Prestia, Louis Johnson, Jerry Jemmot, Bernard Edwards, Paul Jackson, Chuck Rainey, Flea, James Jamerson, Pino Palladino, Jaco Pastorius, Alain Caron, Donald "Duck" Dunn, Nathan Watts, Alphonso Johnson, Verdine White, and many others!
Each proposed groove is then analyzed rhythmically and harmonically, and, indeed, I have tried to make you understand why I use certain scales, arpeggios, substitutions, "out" notes and "in" notes, etc., etc. So many examples are offered in two keys, to give you the imput to play everything studied, in as many keys as possible. All proposed grooves have, attached, the audio example recorded by myself at original speed, the same example at half speed, backing track and drum loops. There will also be videos attached, which I will point out later. The MAIN purpose of this book, is for you to take cues from my examples to compose your own bass lines. Try to understand and internalize each and every element suggested, to create your own musical "vocabulary," and have fun modifying my lines with your "taste," and , slowly, to create your own. Don't just read the tabs and try to resonate what I have done, this may suit you only on a "technical" level, but that is not the purpose.
The proposed examples have no order of any kind (difficulty, era, style, or otherwise), precisely because I would like to keep your interest up to the last groove, and because, the difficulty of a given bass line, is subjective!