Jumping into generic stuff, i.e. not bass specific.
I found Pentatonic KHANcepts by Steve Khan opened a few doors for me. Over chord, so and so, what scales, modes, and or pentatonic scales are open to me.
I also enjoy looking at what is available in the Jamey Aebersold Jazz catalog, aka www.jazzbooks.com
How to play the piano despite years of lessons by Ward Cannel and Fred Marx is chuck full of useful tid-bits of information. Yes, it's for the piano, however, it is a great theory read.
How to play from a fake book by Michael Esterowitz. Treble and bass clef notation. I found the bass clef information to have value.