This is a classic science fiction novel by Edward Elmer Smith ("Doc Smith"). 'They were four of the greatest minds in the Universe: Two men, two women, lost in an experimental spaceship billions of parsecs from home. And as they mentally charted the Cosmos to find their way back to earth, their own loves and hates were as startling as the worlds they encountered.' This work is part of our Vintage Sci-Fi Classics Series, a series in which we are republishing some of the best stories in the genre by some of its most acclaimed authors, such as Isaac Asimov, Marion Zimmer Bradley, and Robert Sheckley. Each publication is complete with a short introduction to the history of science fiction.