Curtis Cover Gallery

On Thursday I received a comment from brino puzzul about one of the cover galleries I posted back in August 2011. To quote brino, "I'd really like to know who Curtis (the illustrator of the cover of All the Traps of Earth is or was. Nice cover and original style, very similar to that of Simak's City that is one of my favorite covers ever."

I  have to admit that I know nothing of Curtis, nor had I made the connection between the two covers mentioned above. However, I do know of one other cover signed by Curtis from the same publisher in the same period, so we have two, possibly three examples of his work, which I'll post below.

If anyone can add anything, please drop me a line.

All the Traps of Earth by Clifford D. Simak
Four Square Books 993, 1964, 143pp, 2/6. Cover by Curtis

The First Astounding Science Fiction Anthology ed. John W. Campbell, Jr.
Four Square Books 1166, 1964, 320pp, 5/-. Cover by Curtis

City by Clifford D. Simak
Four Square Books 1250, 1965, 188pp, 3/6. Cover by Curtis?