It was first published in the magazine Galaxy Science Fiction for March, 1956, and first appeared in book form in the anthology The World That Couldn't Be and 8 Other SF Novelets (Doubleday, 1959).

[4][7] The story takes the form of a first-person narrative by the protagonist, time-traveling hunter Reginald Rivers, told to Mr. Seligman, a prospective client of his time safari business.

Rivers informs the client that he is not big enough to hunt the dinosaurs of the Cretaceous period and illustrates his point with an extended anecdote from a previous expedition, which forms the main portion of the tale.

One of them, Courtney James (based on Jack Parsons[8]), is a vain, arrogant and spoiled playboy; the other, August Holtzinger, is a small, timid man recently come into wealth (time safaris are not cheap).

Later, after the expedition has returned to the present, James convinces Professor Prochaska, the inventor of the time chamber, to send him back to the Cretaceous again but at a moment just prior to the emergence of the safari's earlier visit.

[12] A tenth tale of Rivers, "Gun, Not for Dinosaur", authored by Chris Bunch, later appeared in Harry Turtledove's 2005 tribute anthology honoring L. Sprague de Camp, The Enchanter Completed.

"[14] Sam Moskowitz, who felt de Camp's "plots less incisive" during this period, cited this story as an "outstanding exception" discussing "with an air of quiet authority the problem of what type of gun and what methodology were best suited to shooting dinosaurs.

"[2] Harry Turtledove deems the piece a "classic, ... at the same time a fine character study, a meditation on time-travel paradoxes (here treated as something the continuum seeks to avoid rather than a likely result of voyaging into the past), and a splendid re-creation of a vanished world.