"The Planet of Illusion" by Millard V. Gordon is a science fiction tale that follows the crew of the spaceship "Astralite" as they stumble upon a mysterious red planet while journeying through space. Suddenly, the "Astralite" finds itself being chased by deadly ships that want to destroy them but the crew quickly realizes that their attackers are a illusion. The ships and inhabitants are not truly in their physical reality. Through this encounter, the crew learns that they were able to glimpse another universe where their ship was perceived as an anomaly. The crew decides they will return to explore this phenomenon, showing they have more curiosity and will continue to adventure.

The Planet of Illusion
By Donald A. Wollheim
A desperate space crew on board the "Astralite" must escape an alien planet consumed by sinister illusions, where the line between reality and perception blurs, after being attacked by deadly ships.
Summary
About the AuthorDonald Allen Wollheim was an American science fiction editor, publisher, writer, and fan. As an author, he published under his own name as well as under pseudonyms, including David Grinnell, Martin Pearson, and Darrell G. Raynor. A founding member of the Futurians, he was a leading influence on science fiction development and fandom in the 20th-century United States. Ursula K. Le Guin called Wollheim "the tough, reliable editor of Ace Books, in the Late Pulpalignean Era, 1966 and '67", which is when he published her first two novels in Ace Double editions.
Donald Allen Wollheim was an American science fiction editor, publisher, writer, and fan. As an author, he published under his own name as well as under pseudonyms, including David Grinnell, Martin Pearson, and Darrell G. Raynor. A founding member of the Futurians, he was a leading influence on science fiction development and fandom in the 20th-century United States. Ursula K. Le Guin called Wollheim "the tough, reliable editor of Ace Books, in the Late Pulpalignean Era, 1966 and '67", which is when he published her first two novels in Ace Double editions.