Doubleday, 1952, 203 pages
High above the planet Florinia, the Squires of Sark live in unimaginable wealth and comfort. Down in the eternal spring of the planet, however, the native Florinians labor ceaselessly to produce the precious kyrt that brings prosperity to their Sarkite masters. Rebellion is unthinkable and impossible. Living among the workers of Florinia, Rik is a man without a memory or a past. He has been abducted and brainwashed. Barely able to speak or care for himself when he was found, Rik is widely regarded as a simpleton by the worker community where he lives. But as his memories begin to return, Rik finds himself driven by a cryptic message he is determined to deliver: Everyone on Florinia is doomed . . . the Currents of Space are bringing destruction. But if the planet is evacuated, the power of Sark will end--so some would finish the job and would kill the messenger. The fate of the Galaxy hangs in the balance.
In my experience, Asimov was better with short stories than with novels. He had an encyclopedic knowledge and he wrote great plot twists based on clever science-based ideas, but his characters were always a bit cardboard (especially his women, who were not Heinleinian sex objects but more like woman-shaped plot devices).
The Currents of Space is part of a "Galactic Empire" series that predates Foundation, but is perfectly fine as a stand-alone novel. Being rather short, it reads like one of Asimov's short stories extended to novel length, but it is still trim and nicely paced, with a variety of character goals and motivations even if not much variety in actual character personalities.
The inhabitants of the planet Florinia harvest "kyrt," which can be made into the most desirable cloth in the galaxy. For some reason, kyrt can only be grown on Florinia: people have tried taking kyrt seeds to other planets and reproducing the exact environmental conditions of Florinia, but everywhere else in the galaxy, it's just cotton.
Florinia is ruled by the wealthy Sarkites, who profit from controlling the sole source of kyrt, and who treat the Florinians like serfs. Florinian society is divided into the laboring class and "Townsmen," who are the local representatives of Sarkite authority. They are educated and given special privileges, and so put above the ordinary Florinians. In other words, they're overseers.
Yup, the novel is built around one big, rather obvious metaphor. Though I would say rather than being a metaphor for Southern slave plantations, it read to me more like a planetary Ireland, with the Sarkites, of course, being the English.
Having not thought highly of the last Asimov novel I read, I was pleasantly surprised by The Currents of Space, which had a smart plot and multiple characters all pursuing sensible (from their perspectives) agendas. The resolution explains everything about the mystery of kyrt, the danger to Florinia, and resolves the Sark/Florinia issue.
It was interesting to read another example of sci-fi written in the 1950s. It's not character-driven, the oppression metaphor is obvious but not hammered, and Asimov breaks lots of "rules" like starting with a prologue and writing from multiple POVs in a short novel, sometimes in the same chapter. The style was quite readable, but today's writers' workshops would tell you not to do all the things that the big names of the past did in spades.
Verdict: Classic SF about a planet endangered and a population oppressed, written by one of the greats in the field. Which by itself would not sell a novel to me, since Asimov often leaves me cold, but The Currents of Space blows away a lot of contemporary Hugo nominees for smarts and entertainment value, and even handling still-extant social issues. That said, it's very much a Fifties space opera, for those who love 'em or hate 'em.
Also by Isaac Asimov: My review of The End of Eternity.
My complete list of book reviews.