The quarterly science fiction magazines, eight decades or so ago, were pretty massive – this 144-page “Interplanetary Number” comes in at 8.5″ wide by 11.5″ tall (21.5 x 29 cm), so only just fits in a modern scanner. ”Our cover this issue depicts a scene from the story entitled, “The Invisible Ships,” by Harl Vincent, in which an enemy Martian is shown coming into the disabled space ship from earth, the entire crew of which ship is paralyzed by the rays of the Martians.” The cover was by Leo Morey, who also provided interior illustrations for that story, and “Extra-Galactic Invaders” by J. Schlossel. Wesso illustrated the John W. Campbell story, while “Moon People of Jupiter” has some typically detailed and imaginative illustrations by Frank R. Paul.


Back in 1931, 50 cents was quite a chunk of money... regular sf magazines didn't reach that price point until the late fifties, and there was a lot of inflation in those three decades. So, there were some avid sf readers back then!