It was first published in paperback by Del Rey/Ballantine in August 1978 as a volume in its Classic Library of Science Fiction.

[1] The book contains thirteen short works of fiction and an afterword by the author, together with an introduction by editor J. J.

He notes that "dispassionate, resourceful scientists — human or alien — are usually the heroes of Gallun's stories.

He finds "one good quality that clearly comes across" in the author's fascination "with natural events or scientific phenomena that seemingly could not take place within the bounds of known science" that he "greatly enjoyed [demonstrating] might be plausibly and scientifically viable" in "stories [that] usually attempted to encourage wonder at what science might be capable of explaining."

Nonetheless, he feels Gallun "is probably best seen as an historical example of a bygone day," who "might still occasionally inspire scientific awe in some, but ... is more likely to leave one fairly cold.