Leslie Fiedler cites documents from Poe's surviving letters to support his argument that Poe's only finished novel was an attempt to emulate the success of Fenimore Cooper's adventure-books. PYM was not successful with a majority audience, and Poe only attempted one other novel-length work, the uncompleted JULIUS RODMAN.
PYM is a corker, though. Like many Poe works the main story takes place within a frame, as the main character details the story of his experiences at a later date, though the full story is given a tantalizing, unresolved conclusion.
PYM is closer in spirit to Stevenson's TREASURE ISLAND than to anything by Cooper, for the titular character is a feckless young man who goes to sea for adventure. Instead Pym suffers an assortment of terrors and tribulations that look forward to the constant perils of serial films, to say nothing of "torture-porn" flicks. Though Pym himself is barely competent to survive the sea's rigors, he lucks out in making common cause with Dirk Peters, a "half-breed" sailor possesses of Herculean strength. Given the author's love of epicene, scholarly characters, Peters is an unusual creation, and the closest Poe ever came to creating a combative hero. Peters lacks the depth of character found in both Cooper's Hawkeye and his Indian buddy Chingachcook, but he does have an almost Conan-esque moment when he uses a knife to slay a giant polar bear.
The phenomenality of PYM starts out as purely naturalistic, but the novel enters literally metaphenomenal waters when Pym and Peters, lost at sea, are picked up by a ship set to explore the South Pole. The ship's crew meets a strange race of Negroid people near the Pole; people who are so black ("How Black Are They--?") that not even their teeth are white. The savages ruthlessly kill everyone in the ship's crew, though Pym and Peters escape for a while. The Americans finally manage to steal a boat from the evil blacks-- as well as taking one of the tribesmen hostage-- and find themselves sailing into a world that gets stranger and stranger. The novel ends on a bizarre note, as the two Americans behold a titanic white human figure waiting at the Pole to greet them.
The narrative breaks off, and an interpolation by another hand explains that though Pym returned to the U.S. and managed to write his story, he died before completing the work, thus leaving the narrative an eternal mystery. Peters is also supposed to have returned, but remains unavailable to anyone inquiring about the adventure. Later authors were more impressed by Poe's PYM than his contemporaries. Jules Verne wrote a rationalistic sequel explaining in tedious detail what Pym encountered at the South Pole. In contrast, H.P. Lovecraft understood that Poe was seeking to evoke the sense of a mysterious, imponderable cosmos. HPL not only incorporated elements of the Poe work into his own "Cthulhu Mythos," he also made frequent use of the trope of the "story that breaks off at the end and leaves the reader guessing."