He gave us I Am Legend. He was one of the best writers Rod Serling ever hired for The Twilight Zone (and it was Matheson, I just learned, who wrote the show's opening and closing narration). He wrote both the short story and the Steven Spielberg-directed film Duel. He gave us -- among so much else -- What Dreams May Come, Bid Time Return (filmed as Somewhere in Time), and The Shrinking Man:
I was continuing to shrink, to become... what? The infinitesimal? What was I? Still a human being? Or was I the man of the future? If there were other bursts of radiation, other clouds drifting across seas and continents, would other beings follow me into this vast new world? So close - the infinitesimal and the infinite. But suddenly, I knew they were really the two ends of the same concept. The unbelievably small and the unbelievably vast eventually meet - like the closing of a gigantic circle. I looked up, as if somehow I would grasp the heavens. The universe, worlds beyond number, God's silver tapestry spread across the night. And in that moment, I knew the answer to the riddle of the infinite. I had thought in terms of man's own limited dimension. I had presumed upon nature. That existence begins and ends is man's conception, not nature's. And I felt my body dwindling, melting, becoming nothing. My fears melted away. And in their place came acceptance. All this vast majesty of creation, it had to mean something. And then I meant something, too. Yes, smaller than the smallest, I meant something, too. To God, there is no zero. I still exist.