Mr. Ampersand brought up the question of full-blooded '50's style Sci-Fi as we were leaving Origins yesterday, and I went into my little song and dance and chanted "Eric Frank Russell" over and over.
I knew him from the classic SF story "Allamagoosa" but a couple of years back I also ran across his "Men, Martians and Machines" in Half-Price Books and loved it (You want know where they stole Star Trek from? This is it.)
Since then I've also read his novels: "Wasp" (how to run an effective counter-insurgency) and "The Great Explosion" (finding lost colonies that would rather stay lost, thank you), and "Sentinals from Space" (mutants, teeps and watchers from beyond the solar system) and "Three to Conquer" (more on teeps.) You read these novels and short stories and you can see where so much of later SF came from.
Excellent writer and one of the formative authors of the genre.