It sure sounded familiar, so I went to GCD to look it up. The story was retitled "Princess of the Atom" and was published as an almost-unheard-of 2-parter in CAPTAIN AMERICA COMICS #25 (Part 1- 21 pages) and #26 (Part 2- 25 pages). I think I'd seen the story mentioned (along with a reprint of the splash title page) somewhere in ALTER EGO, and it just missed being reprinted in MARVEL MASTERWORKS: GOLDEN AGE CAPTAIN COMICS VOL. 7 -- if there'd been a Volume 7. Unfortunately, the whole GA Masterworks program ground to a halt after CAPTAIN AMERICA COMICS Vol. 6... darn the luck! "The Girl in the Golden Atom" was published in 1922, but WEIRD SCIENCE #12's "Into the Microcosm" was specifically springboarded by Henry Hasse's 1936 AMAZING Stories novelette, "He Who Shrank". In either case, neither Cummings nor Hasse was the first to chronicle the exploits of a micronaut -- that would be Fitz-James O'Brien's "The Diamond Lens" from 1858, in which the scientist-narrator invents a powerful new microscope with which he's able to observe for the first time, a microverse within a drop of water (complete with beautiful princess, of course). And since this is a comics board, I guess I'd be remiss if I didn't at least mention in passing Harlan Ellison's epic Hulk-Jarella romance in "The Brute That Shouted Love at the Heart of the Atom!" (and of course, "The Micro-World of Dr. Doom" would not have been complete without the beautiful Princess Pearla around). All of these microverse stories are missing the essential elements of both The Incredible Shrinking Man and Siegel's story "The Evil Men Do", however -- those stories don't focus on microworlds at all, but on the helplessness felt by a human being reduced to a tiny scale in OUR world, and hopelessly trapped by forces out of his control (and also, not incidentally, Stan Lee's "The Man in the Anthill" in TALES TO ASTONISH). But hey, giving credit where it's due, let's not forget the 1940 Ernest B. Schoedsack (of KING KONG fame) film, DR. CYCLOPS, produced by Merien C. Cooper for Paramount, either. This is not to take anything away from Matheson's novel, for he wisely focused his writing on the very real human aspects of frustration and panic of a man trapped in an incomprehensible situation.