I am not aware much with Sci-Fi literature, that’s why I didn’t hear about Robert A. Heinlein, who is considered one of the “Big Three” of science fiction; the other two are Isaac Asimov (who wrote “I, Robot” and “Bicentennial Man”) and Arthur C. Clarke.
My eyes caught few quotes by him which seemed pretty interesting:
“When one teaches, two learn.”
“A generation which ignores history has no past and no future.”
“If you would know a man, observe how he treats a cat.”
“Never try to teach a pig to sing; it wastes your time and it annoys the pig.”