Parts of this book were published as separate short stories in The Magazine of Fantasy and Science Fiction:

“Time Patrol” May 1955;

“Delenda est” Dec 1955;

“Brave To Be A King” Aug 1959;

“The Only Game in Town” Jan 1960;

“Gibraltar Falls” Oct 1975.

Guardians of Time collection was first published in Oct 1962; “Gibraltar Falls” was added to it in Oct 1981 edition.