It was originally serialized in the magazine Astounding beginning in 1947, and was first published in book form in 1954 by Fantasy Press in an edition of 4,874 copies.

The story takes place twenty years after the close of Second Stage Lensmen, and focuses on the five children of Kimball and Clarrissa Kinnison: a boy and two pairs of twin girls.

Spurred into action by a series of seeming untraceable terrorist attacks, and other unexplainable events in both the First and Second Galaxy, Kimball asks the other Second Stage Lensmen to help him trace down the source of the troubles.

The Second Stage Lensmen address the problem in their usual style: Kimball is energetic and direct, Nadreck is cautious and thorough, Clarrissa gets sent to Lyrane II again, and so on.

All of the lensmen are led to essentially the same conclusion: the hitherto unknown planet of Ploor is the location of the race controlling the remnants of Boskone.

Not only are the massive fleets of Civilization equipped with single-shot "primary" and "secondary" beam weapons, they now have super-atomic (total conversion of mass to energy) bombs, also deployed by the thousands.

The mental bolt, with the massed power of every Lensman, every Arisian, and the Children of the Lens behind it, and guided by the Unit strikes, and penetrates, Eddore's defenses.

While Galaxy reviewer Groff Conklin faulted the novel for its "style varying from the irritating to the infantile" and "its characters [not] much more than cardboard cutouts," he acknowledged that the Lensman series, "a sort of overblown fairy tales for modern juveniles," was "a pretty solid achievement.

"[1] Anthony Boucher, saying that he found Smith's works unreadable, nevertheless noted that "I know a number of rational people who insist that they represent the acme of hypergalactic adventure.

Smith included in his Expanded Universe, American author Robert A. Heinlein wrote:[4] The Lensman [series] was left unfinished.

He was persuaded to run it by a science fiction fan named Ed Wood who pointed out how important the story had been to the magazine before it became established.