By Paul Di Filippo

Thunder's Mouth. 370 pp. $16.95

Every year or thereabouts, Paul Di Filippo makes a strafing run across the sci-fi genre, flying in from some postmodern geography peculiarly his own (I imagine his home to be a geodesic fantasy populated with bongo-playing beatniks, dogs wearing bandannas, the odd cartoon character, an astrophysicist or two, and half a dozen notable authors) to blow a few holes in our expectations with a short-fiction collection. The latest, "The Emperor of Gondwanaland and Other Stories," his eighth collection in the past decade, shows that being prolific has in no way dimmed his talent for invention.

A typical Di Filippo story might take place in the mind of a youthful Cotton Mather, in Emily Dickinson's parlor, or in an infinitely long city that is scarcely a block wide. It might affect a pastiche of J.P. Donleavy, be told in 17th-century prose or a futuristic patois and deal with talking beavers or Chinese astronauts. Actually, there is no such thing as a typical Di Filippo story. Over the years he has become a literary quick-change artist, adept at shifting between personas, styles, subgenres and milieus (often within the same story), and all his work bears the stamp of good-hearted wit and intelligence.

Though the 18 stories that make up "The Emperor of Gondwanaland" exhibit some unevenness, the majority of them serve their author well, and the best are exemplary. In "Observable Things," 13-year-old Cotton Mather -- by his own account, something of a voyeur -- joins Solomon Kane, the Puritan hero from Conan-creator Robert E. Howard. It's the stuff of pure pulp, but in Di Filippo's hands it becomes historical commentary.

In the title story, one of those lonely souls who depend on their PCs for emotional sustenance investigates Gondwanaland, an imaginary nation that he thinks exists only on the Internet -- until he meets one of its citizens. In "Alloura," Di Filippo reimagines the fairy tale "Puss 'n Boots" as a space opera, and gonzo science is on display in "And the Dish Ran Away With the Spoon," wherein a woman is seduced by a bleb, a "spontaneous assemblage of information" that is "embedded in an Aeron chair mated with several other objects: a Cuisinart, an autonomous vacuum cleaner with numerous interchangeable attachments, an iPod, and a diagnostic and therapeutic home medical tool known as a Life Quilt."

Di Filippo is a joyful writer. He exults in what he does and wants his audience to exult along with him. This comes across in the detail of these imagined worlds and in his delight in language, most often evidenced by his tendency toward baroque usage and by a talent for technospeak. Here, for instance, the description of something as mundane as a pharmaceutical product becomes a sort of cyberpunk poetry: "Sayshe8, a variety of bacillomyces that generated an appetite-suppressing molecule. Stomach-stapling in a teaspoon."

In "Clouds and Cold Fires," a group of talking beavers, the appointed wardens of a planet, are ordered by a godlike authority, the Overmind, to travel to an area where the last brutal relics of humanity live and prevent them from "launching an assault on the tropospherical mind." And in "A Monument to Afterthought Unveiled," Robert Frost, his vein of poetry run dry after the death of his first wife, begins writing horror stories for Weird Tales under the editorial stewardship of H.P. Lovecraft. Both of these pieces, with their embedded love stories, touch upon -- yet only lightly -- deeper emotional concerns than do the others in the book, and you have to wonder if Di Filippo is holding back from exploring his underlying themes. He's insightful and skillful enough to give his stories more moral weight, and I, for one, would have welcomed it.

Di Filippo's work harks back to the Golden Age fantasists, yet also recapitulates the cyberpunks and seems to anticipate, with its brimming energy and eagerness to experiment, a livelier brand of fantasy writing than what prevails today. If he did not exist, we would have to invent him using, say, a spontaneous assemblage of information, an ionic fountain and a rhyming dictionary with a vocal attachment that allows it to speak in various meters and, on occasion, if it feels so inclined, to sing.