Overstreet says the story is actually by Williamson-Krenkel-Orlando, not Williamson-Krenkel-Frazetta. Not sure exactly what their source is, other than they say that's what Williamson said somewhere.
Anyway, everybody else, enjoy the book. It's an absolutely beautiful piece of work, which really counts as the unofficial first Frazetta Buck Rogers cover and unofficial first Williamson Flash Gordon story. (Buster Crabbe was, of course, the actor who played both Buck and Flash in serials.) The writing, not so spectacular. But it looks amazing.
My huge thanks to Geo for the wonderful work he did making my copy look so good. Even if he did suggest I would regret it if I didn't let him do the scans & edits when he heard I had located an affordable copy.