I'd like to make a suggestion to all jazz bassists, really. If you are fortunate enough to live around a metropolitan area where fine jazz musicians are located, search out a player of another instrument (sax, piano, trumpet, etc) whom you would love to play with some day. Take lessons from him. (I'm not saying to stop your classical, or jazz lessons with your bass teacher.) Who better to tell you what he likes to hear behind his solos or thru his compositions than a horn player, guitarist, piano player, or whomever. This is how I learned Joe Henderson's book, became life-long friends and performed with him. What I didn't know is that Joe's first instrument was the double bass! He also constructed a 72 bar walking bassline over his composition, 'Isotope' which are brilliant basslines from the mind of a genius. I hope this may be invaluable advice for some of you!