Rivers of Time is a 1993 collection of short stories by science fiction and fantasy author L. Sprague de Camp, first published in paperback by Baen Books. All but two of the pieces were originally published between 1956 and 1993 in the magazines Galaxy, The Magazine of Fantasy & Science Fiction, Analog, and Asimov's Science Fiction, and the Robert Silverberg-edited anthology The Ultimate Dinosaur. The remaining pieces were first published in the present work. The book collects the author's nine tales of time-traveling hunter Reginald Rivers, the hero of his 1956 classic, "A Gun for Dinosaur". He wrote another Rivers story in 1990 to fulfil a request by Robert Silverberg for a dinosaur story for his 1991 anthology The Ultimate Dinosaur; afterwards, de Camp added to the sequence until he had enough stories for a book.