I'm breakin' open my Complete Guide to Drawing Illustration Cartooning and Painting again so I figured I'd post a couple of my favorite pages.
This book is looong out of print, my copy is from 1948, but if you happen across a copy on Ebay or something it's a really great book. With contributions by (besides Milt Caniff, Alex Raymond, and Jerry Siegel shown above) there's also work by guys like George Bridgman, Dean Cornwell and Hal Foster.
Not that you can tell from through the intenets but it also has that great old book smell. Not the old ladies basement old book smell, the GOOD kind of old book smell.