Isaac Asimov was my #1 favorite author growing up, and still is today. I read and re-read his Robot series. His three law of robotics, great stuff. The Gods Themselves – wonderful, very pointed. Asimov, Ray Bradbury, and Arthur C. Clarke were what I called the ABCs of classic sci-fi. There were others, like Robert Heinlein, Theodore Sturgeon, etc. So many others.
Edgar Rice Burroughs was also on my list of favorites. Known for his Tarzan series, it was his Barsoom series (a.k.a., John Carter of Mars) and his Pellucidar series (Hollow Earth) were my favorites. I even named my daughter after a character in Synthetic Men of Mars (Janai of Amhor – because I liked the name).