From Air Wave: "Who Rubbed Out the Editor?" by Murray Boltinoff, Harry Levy and Charles Paris, Detective Comics #70 (December 1942)
It may seem like Marvel invented the concept of the publisher's offices existing within their superhero universe - they certainly ran with it - but there are precursors. Case in point, this story in which Air Wave solves comic book-related murders! Now, in the DCU, the publishers have generally been stranded on different Earths. Barry Allen could read Golden Age comics because the stories took place on Earth-2. Modern day heroes were "written" from Earth-Prime. But here, Kolossal Komics operate out of Air Wave's Gotham, which in the Golden Age idea of things may or may not be Batman's. Kolossal seem to be a thinly veiled parody of DC/National, with such characters as the Keen Arrow, Showerman and The Sunburned Kid (Green Arrow, Superman and the Star-Spangled Kid). And Air Wave couldn't have solved it without knowing SOME comics lore, so that's cool.
This is also the first One Panel entry I write after the passing of Mike, of Mike's Amazing World of Comics. This series couldn't be done without the immense work he put into his site, tracking comics publications. How do I know which comics came out which month? Mike's. And he ensured his legacy, making sure the site would continue without him. When it's my time, I hope I'll have been smart enough to also secure my online holdings. Thanks for everything, Mike, you were one of the greats.