"Gulf" is a novella that was first published in Astounding Science Fiction in 1949, though it is most readily found in the collection Assignment in Eternity (available in various editions). The title refers to the yawning gulf between ordinary human beings and a new evolutionary breed of supermen.
The story is of special interest as an early attempt by one of the most prominent SF practitioners to explore the implications of people with extraordinary capacities... and how those people might relate to the rest of us. The answer, in a nutshell, is paternalistically: by standing apart from the rest of humanity, forming their own shadowy organisation, and taking decisive, competent action, as and when necessary, to save us from our follies. As acknowledged in the dialogue among its characters, there is a strong anti-democratic theme in "Gulf". It expresses distrust for democratic electorates, public officials, and the agencies of government: modern-day risks have reached a point, Heinlein seems to suggest, where we need ultra-competent people to take charge for our own good.
The novella begins convincingly with a scene where the main character - secret agent Joe Greene, although we yet don't learn this name - attempts to avoid detection by enemy agents. He is, nonetheless, followed and soon captured. Imprisoned, he meets another prisoner, "Kettle Belly" Baldwin, and they communicate by playing a coded card game. Baldwin later turns out to be one of the new breed, and he suspects (rightly) that Joe is also one; as becomes apparent, Joe merely needed recruitment, briefing, and special training.
Heinlein's depiction to this point is concise, well-paced, and fascinating. As it turns out, the new breed of supermen (and superwomen) are characterised mainly by the ability to think with extraordinary swiftness, clarity, and accuracy. Long before this ability is explicitly identified, we see Joe using it as he engages brilliantly and decisively with his enemies.
Unfortunately, the story seems to spiral increasingly out of the author's control. It might, perhaps, have worked better as a full-length novel. By the end, much is being conveyed to us through exposition, long speeches, and reports of off-stage action, all to an extent where the second half of "Gulf" seems amateurish by today's standards for genre fiction. There may be biographical reasons why Heinlein wrote in this way: perhaps he needed to cram the events into far less space than was truly required to convey them (and the weighty themes) via onstage action and dialogue, and through the thoughts and perceptions of the viewpoint character. The skill shown in the opening pages, in particular, suggests that Heinlein was equipped for the creative task, but for whatever reasons he produced a story that is far from an artistic success.
"Gulf" also dates more sadly than much of Heinlein's other fiction from this period - or at least the passage of time dates it severely for me. While I can get into the spirit of a story about Venus and Mars as habitable planets (accepting this partly as a convention, and partly as reflecting the scientific uncertainty about the surfaces of those planets in the 1940s and 1950s), I find it much more difficult to swallow the pseudoscientific gobbledegook in stories, such as "Gulf", that dabble with ideas of Korzybskian "general semantics" dialled up to eleven to suggest that study of general semantics could grant extraordinary mental powers to someone with the right potential. This plot element might have been more acceptable if simply introduced as a kind of magical technology, without ponderous explanations suggesting that we entertain it seriously.
"Gulf" is a story of some historical importance in Heinlein's development as a writer, and in the development of the science fiction genre. It contains some fine, swift-paced superspy writing, but eventually it seems to fall apart under its own weight of themes and events. Once again, it might have worked better if the second half had been expanded to bring the total to full novel length. Alas, that didn't happen, for whatever reasons, and we're stuck with the story as is.
As is well-known to fans of Heinlein, Friday (1982) can be read as a sequel to "Gulf"; it includes Kettle Belly Baldwin among its cast of characters, and it deals, once again, with relationships between ordinary human beings and individuals with extraordinary abilities. I haven't read Friday since shortly after it was first published, over thirty years ago, so I'll be returning to it soon. At the time, I viewed it as a return to form for Heinlein after a sequence of very long and self-indulgent books (beginning in 1970 with I Will Fear No Evil). We'll see how well it has aged. But first, I plan to read (in most cases re-read, since I've read most of Heinlein's body of work), some more of the earlier novels.