Wow - didn't know there were that many Martian OR Conan novels (especially Conan - I only know the 2 movies with Ah-nold)! Re: the latter, it looks like L. Sprague de Camp wrote a number of them - loops back to Oz as he also played in the Oz sandbox in his "Compleat Enchanter" series.

Thanks for the tip re: Shanower! Not read any of his, but am on the lookout!