Invaders from the Infinite is a science fiction novel by John W Campbell Jr., first published in 1932.

The famous scientific trio of Arcot, Wade and Morey, challenged by the most ruthless aliens in all the universes, blasted off on an intergalactic search for defenses against the invaders of Earth and all her allies.

World after world was visited, secret after secret unleashed, and turned to mighty weapons of intense force - and still the Thessian enemy seemed to grow in power and ferocity. 

Mighty battles between huge space armadas were but skirmishes in the galactic war, as the invincible aliens savagely advanced and the Earth team hurled bolt after bolt of pure ravening energy - until it appeared that the universe itself might end in one final flare of furious torrential power…

This is the last book of a trilogy with the same characters. The first two novels in the trilogy are The Black Star Passes and Islands of Space.

Text from original book-cover:

”The Alien spaceship was unthinkably huge, enormously powerful, apparently irresistable. It came from the void and settled on Earth, striking awe into the hearts of all who saw it. Its burden however, was not conquest – but call for help!

First contact was a job for the brilliant team of scientists, Arcot, Wade and Morey, explorers of the ISLANDS OF SPACE. And what they learned was an offer of an alliance against an invading foe so powerful that no known force could turn them back!

John W. Campbell’s INVADERS FROM THE INFINITE is a veritable odyssey of the universe, exploring world after world, and uncovering cosmic secret after cosmic secret. Here is a classic novel of super-science that may never be surpassed.”

John W Campbell Jr., (1910-1971) was an American science fiction writer and editor. As editor of Astounding Science Fiction (later called Analog Science Fiction and Fact) from late 1937 until his death, he is generally credited with shaping the so-called Golden Age of Science Fiction.