THE HOLLOW EARTH By Rudy Rucker Morrow. 308 pp. $18.95

IN THE summer of 1836, shortly after he had married his 13-year-old cousin Virginia Clemm, Edgar Allan Poe wrote an article for the Southern Literary Messenger (of which he was editor) applauding the efforts of Jeremiah N. Reynolds to have the U.S. government finance a scientific expedition to the South Polar Sea. Poe was Reynolds's advocate on two later literary occasions, and he was also reported to have called out Reynolds's name repeatedly as he lay dying and delirious in Baltimore in 1849. From these two bare hints, Rudy Rucker, a science-fiction writer and a fellow Virginian, has concocted an entertaining pastiche partly after the manner of Poe's own mock-chronicle of sea-faring adventure and horror, The Narrative of Arthur Gordon Pym.

The first and by far the more accomplished half of Rucker's The Hollow Earth takes Huckleberry Finn as its model rather than any work by Poe -- a happy choice, since Poe was no great shakes as a novelist, as those who've read his Pym are painfully aware. Rucker's narrator Mason Algiers Reynolds (no relation to Reynolds of Antarctica, who also figures in the plot) is a 15-year-old farmboy from Hardware, Va., whose troubles begin when he is dispatched to Lynchburg with the total year's output from the Reynolds farm, three barrels of corn whiskey. Diddled out of the whiskey proceeds and a fugitive from justice, Mason, with Otha, the family's slave, stows away on a barge bound for Richmond, where Mason befriends Poe, gets a job at the Southern Literary Messenger, and becomes a boarder in the Poe household. Rucker paints in the local color and period detail with panache, and in the characters of Mason and Otha he's accomplished a creditable variation on Huck and Jim, aided by the R-rated liberties allowed to latter-day novelists.

Like Huck, Mason views the world with a shrewd naivete, never shrewder than when he's reporting on the Great Writer:

"Edgar Allan Poe: Poe, the poor, half-educated orphan posing as an American man of letters; Poe the sham priest of our nonexistent culture. Watching him work in the office this week, I'd quickly learned to see through him. The manuscripts he sent to New York publishers kept coming back rejected. The reviews he wrote for the Messenger were simple tirades butted in with generously scissored out excerpts of the pages in question. The multilingual sayings he set into his essays were culled wholesale from foreign phrase books. There wasn't an honest bone in his body, and he still owed me fifty cents."

Though Poe was never the reprobate portrayed in the slanderous memoir of his literary executor, the Rev. Rufus Griswold, nor even the poet maudit of Baudelaire's imagining, these images have stuck, despite all later scholarship, and Rucker's Poe is a comic version of these myths -- not just a drunk, a drug fiend, a card shark and a cradle robber, but a buffoon in all these capacities as well. This would surely be unfair in a biography, but here it is simply good fun, as irresistible as it is irresponsible. Indeed, only those who know how Rucker is stacking his deck will be able to appreciate much of the book's sly, referential irreverence.

At exactly the half-way point of the story, Mason, Otha, J.N. Reynolds, Poe and a dog named Arf fall through the hole at the South Pole, and The Hollow Earth becomes a Wonder Journey of a somewhat formulaic sort, with lots of strange plants and animals, Polynesian-style natives, and a nubile maiden who says things like "Emthonjeni womculo. Thul'ulale" before bedding down with the hero inside a giant flower. This is the territory of Edgar Rice Burroughs rather than Edgar Allan Poe, who, accordingly, tends to vanish from the tale. Rucker never wants for new inventions, but they don't add up to a real adventure, not even of the picaresque variety. The plot doesn't get under weigh again until the explorers return topside.

There Rucker has one more trick up his sleeve -- a confrontation between the real Poe of history and Rucker's Poe, whose skin has become black during his sojourn under the Earth. Like so many other novelists, Rucker gets hasty as the end of his book hoves into view, and the showdown between the two Poes fails to yield its comic potential. Even during its duller stretches, however, The Hollow Earth has enough going for it, in a Paul-Bunyanish way, to make it worth reading. Thomas M. Disch's novel, "The M.D.: a Horror Story," is forthcoming.