Above: a SHOWME cover by Mort Walker from May 1947. More Mort Walker images here: Mort Walker on MU Campus.
I've decided Mort Walker is the Mozart of cartooning. Dale Smith writes for the Mizzou [University of Missouri] Journal:
"At age 13, he wrote a regular strip for the Kansas City Journal. By age 15, he already had sold 300 cartoons, and by 17 he was a lead artist at Hallmark, where he helped launch a line of humorous cards. While a student at Mizzou, he worked as a freelancer for Hallmark, illustrating several cards a week, in addition to taking courses, editing Missouri Showme, serving as president of the Kappa Sigma fraternity, working on the Savitar, writing plays and more.
"'I’ve always had too much to do,' says Walker, BA ’48, who still writes Beetle Bailey. 'For me, school was a center for my activities, but not necessarily a center of learning.'"
In this expert video by Nicholas Brenner, we can see just a fraction of Mr. Walker's output during those early years, as well as an interview with him from October 22, 2010, upon the occasion of dedicating the new MU Student Center.
Checker Books has reprinted the BEETLE BAILEY comic strip, beginning with BEETLE BAILEY THE FIRST YEARS 1950-52. Take a peek here at some the pages. These are well reproduced, thorough reprints, chock full of notes and additional cartoons and photos.