FOR ABOUT 15 years I've dreamed of reviewing a book by Ursula Le Guin. The reason is simple. I love science fiction. She is either the best or one of the two best science fiction writers in America, and it would have been pleasure to praise The Left Hand of Darkness or some new novel about the star system Gamma Draconis.

I also love heroic fantasy. Her Earthsea trilogy, centered on Ged, the impulsive young magician of the Archipelago, gives magic the somber power it must really have if it really exists, while most fantasy firmly trivializes it. It would have been joy to review a book about Ged.

Now that I finally have the chance, I seem to be a few years too late. It's not that Le Guin's powers have declined. If anything, they're still growing. It's two quite different problems. One is that her interests have clearly shifted. Two of her recent books are collections of poems. Two others are ordinary mainstream fiction. Well, not ordinary -- both the novel Malafrena and most of the short stories in the collection called Orsinian Tales are superbly told -- but their subject is ordinary life on the planet Earth. Malafrena is a historical novel, laid in that part of Europe where western and Slavic cultures come together, about 10 years after the fall of Napoleon. Orsinian Tales offers glimpses of the same region at various intervals between 1150 and 1965. Le Guin swims well in the mainstream, but her glory has come in leaping the cataracts of science fiction.

The other problem is that insofar as she has kept her interest in science fiction -- and the stories in the book I am getting to review are roughly half sf -- she has fallen victim to the common fate of very successful practitioners in the field, a fate sometimes called asimovitis. The symptoms are clearly visible in The Compass Rose.

Asimovitis, like the much older disease cacoethes scribendi, leads to overproduction and underrevision. It has a curious origin. Up until about a generation ago, science fiction was a notoriously low-paid and low-prestige genre. Those who wrote it had to work at high speed to make any sort of living at all. If you finished a story this week and got your $100, you instantly began to plan what you would write next week to make another hundred. Or even another fifty. Take an example from the eponym himself. During the 1940s, Isaac Asimov wrote all the stories that were later collected as I, Robot and all the stories that later became the Foundation trilogy. Trilogy, mind you. (It's as common a form in sf as the sonnet is in poetry.) When he was done, he had earned somewhat under $8,000.

Respect was even scarcer than money. Science fiction ordinarily didn't get reviewed at all, except in sf magazines. It virtually never got picked up in the year's best this or that, virtually never appeared in hardcover, virtually never won prizes. The results were just what you'd expect: a closed society. Science fiction writers huddled together for protection. They invented their own set of annual prizes. They reviewed each other, extremely generously. They began putting out their own inexpensive anthologies, to which they invited all their colleagues to contribute. The colleagues would each dash something off -- a jungle-planet story, a space-warp story, whatever was wanted -- and soon the shoddily printed little book would be out.

Now that science fiction is wealthy and successful, these patterns persist. To this day, almost any sf writer will write something to order for almost any other sf writer or editor who asks. Even Ursula Le Guin will. There's a pleasing modesty and lack of pomp involved; there is also a lot of hasty writing appearing on acid-free paper at high prices.

Take, for example, the longest story in Le Guin's new book. It originally appeared in an anthology called The New Atlantis and Other Novellas of Science Fiction, edited by Robert Silverberg, a man with a bad case of asimovitis. In his preface, Silverberg stresses the fact that the novella form permits a "richness of detail and narrative development" that the ordinary sf story does not. So it does. And for two of the three works he has assembled, the point is relevant. Gene Wolfe's novella "Silhouette" is rich indeed, and the Washington-area woman who writes as James Tiptree Jr., produced her first actual masterpiece in "A Momentary Taste of Being." "Silhouette" is a relatively short novella of 54 pages; "A Momentary Taste of Being" is of more classical novella length at 94 pages.

Then there is the title piece by Ursula Le Guin, the big name of the anthology. "The New Atlantis," 27 pages, is not a novella, not rich in detail or narrative development. It's a competent story on her familiar theme of an oppressive society that proves just a little too strong for the free men and women who defy it. To read it, knowing Le Guin at her best, is something like watching a Porsche being driven entirely in second gear.

Sometimes she doesn't even get into second. Several of the science fiction "stories" are not stories at all; they are conceits, ideas for stories. "Ms. Found in an Anthill" is in fact three linked conceits, one of them breathtakingly successful, two of them dull mechanical variants. "The Wife's Story" is a mere trick. "Intracom" is another trick, but one performed so deftly as to make one cheer for the magician's skill, while still lamenting the absence of much substance.

There is, happily, far better work in the book. There is "The Diary of the Rose," for example. It has a similar theme to "The New Atlantis," and it was written for a similar kind of instant anthology. But because Le Guin found a way of telling the story that obviously challenged her, it does not come out perfunctory at all; it comes out almost unbearably powerful.

And best of all, in the non-science fiction half of the book, there are some stories that go far toward reconciling me to her new interests. "Malheur County" is an apparently simple story of a strong Oregon woman in her sixties named Harriet, her son-in-law Edward (the daughter is dead), her 2-year-old grandson Andrew. What perception is here! It's as fine a study of how strength deals with age as I have ever seen. If the whole book were on the level of "Malheur," its publication would be a major event.

As it is, publication of The Compass Rose is a minor event in the career of a major author.