Here's a darn good article by Todd Leopold about the heritage of MAD magazine. Not much in there about the current publication, which I think is quite funny and worthy of purchase. Leopold writes mostly about Al Jaffee and the illustrators who've survived from his generation. But check it out and click on the links, some of which will take you to good articles that expand on what Leopold writes. And especially check out the gallery of Tom Richmond caricatures of himself and his fellow artists.