Dust-jacket from the first edition

Two men in a spaceship are discussing how empty and cold space is. The first man is a little bit insane and keeps asking questions about how there is nothing sure in space and there is no night or morning. He refuses to believe anything about reality without sufficient evidence and soon becomes skeptical of everything he cannot directly experience. He said that he doesn’t believe in stars because they are too far away. The second man is wandering about the ship when he learns that someone has left the ship, and it is the first man. The first man is still talking to himself and has killed himself by letting himself fly freely through space.