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