Some classic SF...
Hi BR
Campbell wrote some excellent early SF novels - space operas, but intelligent and thought-provoking. "The Mightiest Machine" (c.1934) and "The Incredible Planet" (1949) were a short series in which Campbell covered some very heady speculations in physics and wrote good stories out of the results. Logical extrapolations of ideas inherent in the physics of the time...
The Mightiest Machine
The Incredible Planet... and others
I really enjoyed them despite their age.
Adam