While we're on the topic of si-fi books, have you read Isaac Asimov's books? I love his Foundation Trilogy. And I, Robot was enjoyable too. He's definitely one of my favorite science fiction writers.
I suppose so. Tunnel in the Sky was published in 1955.
I guess the others would have been at around the same time.
If you haven't read them, you should give them a try, just to get a taste of the masters of the last generation.
My favorite is Citizen of the Galaxy, currently reading Between Planets, just finished Starman Jones, my father liked Space Cadet. I also liked The Door into Summer, about time travel. He wrote quite a few books.
Apart from things already told here, I have a large concern for my property, which needs its earth-retaining wall in good condition. Please pray that I can get it fixed without going into debt!