Perhaps you've seen this before... tucked inside an Edward Tufte book about Visual Explanations... or in that New York Dolls documentary... but I thought I'd share it with you here and now. It blends two of my favorite things, music and information design.
This is Reebee's Genealogy of Pop/Rock Music from 1955 to 1978. I hope he decides to continue the chart. If not, I may take a crack at it.

