The Pursuit of the Pankera: A Novel About Parallel Universes by Robert A. Heinlein
This is an alternate novel of The Number of the Beast. Supposedly there was to be two novels published together. This was worth another look since it was new manuscript. This has inspired me to read the original again.
The Star-Master by Ray Cummings
Art and his friend Jim are on a hunting trip where they discover an alien human woman Venta and a midge (a ten inch tall humanoid with insect wings). The four of them are captured by a mad human mad scientist, Curtmann, who has built a spaceship and used it to capture and enslave the planet Venus. Art, Jim, Venta, and their Midge ally Meeta rebel against Curtmann in a final and bloody battle.
Shipwreck in the Sky, by Eando Binder
Post WWII science fiction story where the first man in space crashes into a mile wide dark moon orbiting the Earth. He uses that fact that such a small object has a pitifully low escape velocity that he could run fast enough to reach it. His deorbit maneuver is less believable but still does consider Newtonian mechanics to accomplish it. Binder is a good example of the authors working out the details of space flight before the beginning of actual flight into space.
One-Shot, by James Blish
No pressure! A gambler is asked to make a life or death decision for millions of people betting on his intuition when there are no facts.
The Blaumilch by Lavie Tidar
The Blaumilch is a canal digger that is working on a real Mars that many have imagined to be the Mars of Edgar Rice Burroughs. Daud, an man turned Thark, learns that he wanted to be a worker on the real Mars instead of the warrior on the Mars-that-never-was. A joyful story about becoming something.
The People of the Crater, by Andre Norton
Gavin, an American Aviator, crashes his plane into a crater in Antarctica and finds a fantastic civilization where he becomes the hero of the day. This has a familiar feel and harkens back to the works Edgar Rice Burroughs.
Black-Out, by Joseph Farell
Old scientist on Mars rebuilds telescope to contact the last hope of the dying civilization on Mars — The Earth. Here we have a situation where the lifetime of a civilization (a parameter from the Drake equation) ends signal that is detectable. Mars is making assumptions about cities having roofs and that the city lights are actual signaling apparatus. The loss of those lights are considered a catastrophe for both worlds.
The Expediter, by Mack Reynolds
Future communist dictator attempts an experiment that reveals an interesting and universal hubris by giving an average man the power to fix every problem he comes across.