The Viagens Interplanetarias series is a sequence of science fiction stories by L. Sprague de Camp, begun in the late 1940s and written under the influence of contemporary space opera and sword and planet stories, particularly Edgar Rice Burroughs's Martian novels. Set in the future in the 21st and 22nd centuries, the series is named for the quasi-public Terran agency portrayed as monopolizing interstellar travel, the Brazilian-dominated Viagens Interplanetarias. It is also known as the Krishna series, as the majority of the stories belong to a sequence set on a fictional planet of that name. While de Camp started out as a science fiction writer and his early reputation was based on his short stories in the genre, the Viagens tales represent his only extended science fiction series.

Lyon Sprague de Camp was an American author of science fiction, fantasy and non-fiction literature. In a career spanning 60 years, he wrote over 100 books, both novels and works of non-fiction, including biographies of other fantasy authors. He was a major figure in science fiction in the 1930s and 1940s.