I've just finished the JB book, 'Composing Himself'.
A great read, and certainly filled the gaps on my knowledge of his post-Cream career, of much I was unaware of his multiple projects. He did so much, just never hit that one thing again that could eclipse the popularity of Cream. A shame, as his solo work contains some superb stuff.
Fascinating read. I'd recommend listening to 'Spirit', the 3-CD BBC sessions album alongside - an education in bass playing.
I still like his EB3 tone the best, though!