John W. Campbell 
Invaders from the Infinite [EPUB ebook] 

This is a classic science fiction novel by John W. Campbell Jr., author, and editor of Astounding Science Fiction and Analog Science Fiction and Fact. The novel tells the story of three brilliant scientists, Arcot, Morey, and Wade, and their explorations amongst the islands of space to solve the mystery of the enormous spacecraft that had settled on Earth. What they find is an alliance, but will it be enough to save the planet?
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.