It was like no hell or heaven of which he had ever heard or read, and he had thought that he was acquainted with every theory of the afterlife.
He had died. Now he was alive. He had scoffed all his life at a life-after-death. For once, he could not deny that he had been wrong. But there was no one present to say, "I told you so, you damned infidel!"
Of all the millions, he alone was awake.

Chapter 1 (pp. 3-4) - The Riverworld series - To Your Scattered Bodies Go (1971)