As a kid in the 1950s, I knew that there were three shining stars in the science-fiction firmament: Asimov, Bradbury, and Clarke.

Isaac Asimov was a second-generation “Doc” Smith. Whatever sci-fi tropes and vistas Doc did not invent, Asimov did. Isaac was also, quite probably, one of the brightest men in the world for most, if not all, of his lifetime. His “three Laws” of Robotics, created for his landmark robot series, has been canonized. (See “I, Robot.”) Asimov wrote what has been voted by the community of science-fiction professionals the best sci-fi series of all time, “The Foundation Series.” It was the other influence on George Lucas when he created “Star Wars.”

On the one hand there was Joseph Campbell, author of “Hero with a Thousand Faces,” in which he delineated simply and clearly the heroic myth, which had a major impact on Steven Spielberg . On the other was Asimov, showed in the Foundation books what the future will look like and how we’ll get there; how global domination translates on a galactic scale; how heroes face their demons to defeat evil.

Bradbury captured small-town, rural America in the early part of the twentieth century as no one else has ever done: in a magical web of fearless invention, a love affair with all things possible, and cautionary tales of excess and corruption. He, too, dwelt in grand, metaphoric mythos. But his stock in trade was the human heart, and he knew it quite well.

Arthur C. Clarke was adept at both science and science fiction. He envisioned, and worked out the math for, communications satellites decades before they could be built and launched. For that alone he stands as one of the founding fathers of our modern world. But he also contributed soaring visions of humanity’s relation to space, to other worlds and to alien civilizations. Childhood’s End may be the single best science-fiction book ever written. But he also gave us such mind-expanding gems as Rendezvous with Rama and, of course, his short story, “The Sentinel.” Not familiar with that one? Maybe you know it better from its full-length, collaborative cinematic treatment: 2001: A Space Odyssey—the best science fiction film ever made.

Asimov, Bradbury, Clarke:  the ABC’s of science fiction. They were the visionaries of the field. All who’ve come after have stood on their shoulders. Now, they’re all gone. But their work remains immortal.

Isaac Asimov: 1920 – 1992

Arthur C. Clarke: 1917 – 2008

Ray Bradbury: 1920 – 2012