Short story by L. Sprague de Camp
"Perpetual Motion" is a science fiction short story by American writer L. Sprague de Camp, part of his Viagens Interplanetarias series. It was first published under the title "Wide-Open Planet" in the magazine Future Combined with Science Fiction Stories in the issue for September–October, 1950. It first appeared in book form under the present title in the collection The Continent Makers and Other Tales of the Viagens, published in hardcover by Twayne Publishers in 1953, and in paperback by Signet Books in 1971. It was also included in the paperback edition of The Queen of Zamba published by Dale Books in 1977. This edition was reprinted by Ace Books in 1982 as part of the standard edition of the Krishna novels.[1][2][3] A trade paperback edition in which the story was paired with Richard Wilson's "And Then The Town Took Off" was issued by Armchair Fiction in May, 2013 as Wide-Open Planet & And Then The Town Took Off.[3] The story has been translated into Portuguese, Dutch, and Italian.[1][2]
