MUNGO PARK was a real flesh-and-blood explorer, aScotsman mad about Africa. He made two bold treks into the heart of the dark continent, the first, in 1796, to find the Niger River and determine whether it flowed eastward-- it did--and the second, almost 10 years later, to find out whether the same river simply pizzled out somewhere in the Sahara or twisted south and debouched in the Sea of Guinea. Park was banking on the latter. Between these two adventures, Park wrote a book, married a Scottish lass, fathered four bairns, established a rural medical practice, and pined for excitement and his beloved Africa.

T. Coraghessan Boyle has taken the skeleton of Park's story and shaped it into a sprawling picaresque novel. To it he has added, as a sort of contrapuntal element, the life of a totally fictive character, one Ned Rise. A denizen of London's squalid, gin-sodden underside, Rise repeatedly cons, pimps and befriends his way out of wretched straits only to be hurled back down, time after relentless time. But the worst turn of Fortune's wheel is that which brings Rise into association with Park just in time for the ill-fated second expedition.

Water Music is as densely populated as a Victorian novel, and there are several memorable faces in the crowded field of supporting characters: Ailie Alexander, fiancee and eventual wife to Park, explorer in her own right of teeming microscopic worlds; Johnson, Park's guide, a former slave in the American colonies, an avid reader of Shakespeare, Dryden, and Pope; Georgie Glegg, Ailie's luckless suitor, destined to live in the shadow of the great explorer. All these characters, major and minor, are creatures of obsession, driven to absurd and dangerous lengths by a single governing passion: "What kind of man was he, Mungo Park . . . ? To desert a wife and four children? to lead thirty-six men to their deaths and blow a cringing old Negro to Kingdom Come . . . ? What had he come to? The answer was something he didn't to want to face. Not now, not ever."

With so many people, a lot can happen. A lot does. Boyle is delightfully shameless in his exploitation of melodramatic devices--cliff-hangers (Will Mungo be skewered by ravening Moors?), coincidences (What will happen with a certain dueling pistol?), and miraculous resurrections. He pulls his most implausible inventions with wit, a perfect sense of timing, and his considerable linguistic gifts. He treasures the apt word, the earthy Anglo-Saxonism or the precise Latinate term, and his ear for cockney, brogue, pidgin English and other dialects is sure. If this is the historical novel and the Victorian novel transformed into comic book fiction, it is High Comic Book Fiction, in the manner of John Barth's The Sot-Weed Factor; it also aspires to inclusion in a literary tradition that begins with Cervantes' Don Quixote, a tradition that subverts the established literary conventions (e.g. the knight hero and his quest) in order to mock or demysify a culture's cherished illusions (chivalry, for example).

Water Music, in other words, is ambitious. It takes on nothing less than the mad reasonableness of the 18th century. And to the extent that we are heirs to, and products of, that marvelous Age of Reason, Water Music is about the ways in which we attempt to explain, justify, or ennoble our motives and actions, even when --particularly when-- they are illogical, ignoble, or simply selfish. What better expression of this civilized folly than Europe's scheme to plunder the newly "discovered" world under the noblest of pretenses, a project in which Park's expeditors played no little part.

But Water Music is no anti-imperialist tract. Boyle is more concerned with dark, unexpected, and often absurd turns of human behavior than with broad historical polemic. Thus we are treated to the absurd discrepancy between Park's raw experience and his efforts to communicate it to his fellow countrymen, as when he records his bewildering reception at the court of Mansong, king of Bambarra: "After thanking me profusely, Mansong made me a munificent present in return, with his heartfelt hope that it would aid me in my quest for knowledge." That, as Mungo's guide, Johnson, puts it, is "the purest of bull----." They had been lucky to get out alive. But Mungo knows what will sell back in London.

That London--the London depicted most vividly by Hogarth--serves as the setting for a good part of the novel. And Boyle evokes its extremes, from the fppishness of "Beau" Brummel society to the sordid spectacle of public hangings. This is a baroque world. And the baroque play of violent opposites is the "music" of this novel, accompanying the action whether it unfolds in London, Scotland, or Africa. Frantic, manic energy just straining to break through the polite, civilized forms-- that is the atmosphere that Boyle works so diligently to create and sustain.

To bring all this off is a considerable aesthetic achievement, and Boyle clearly deserves the praise heaped upon him by William Gass and other practitioners of what some call the "new fiction." The "new fiction," if anyone has managed not to hear, is anti-mimetic, self-referential. and highly "textured" prose which eschews the conventions of realism and finds considerable support among academics, particularly those versed in semiotics and other forms of continential critical theory. Not everyone is so enthusiastic about it, however; Gore Vidal dismissed it all as puerile, inbred junk, speciously justified by reams of theoretical nonsense. If these literary ostriches--writers such as Barth, Coover, Pynchon, and Gass--would only take their heads out of the theoretical sand, he argued, they might be able to produce sturdier, more Stendhalian prose.

One does not have to be fully of Vidal's party to be swayed by certain points of his criticism. One may even prefer the fiction of a William Gass or a Gilbert Sorrentino to that of Vidal and still find much that rings true in Vidal's argument. This is not odd, really: Vidal is simply a better critic than maker.

The weakness Vidal touches upon is a certain fundamental emptiness in much of the "new fiction." As much as we might be impressed by verbal virtuosity, we too often go away from these books feeling undernourished. I, for one, find Boyle's vision of man, like that of Barth, Gass, et al., uniformly, predictably, even fashionably bleak. The point he relentlessly presses is that man is a foolish creature and that everything ends with death, though some survive longer than others. Now this might be true--and certain writers might be able to develop it convincingly as something deeply felt and experienced--but with too many of these "new fictioneers" it seems to be a theme of convenience. While great energy is invested in verbal wizardry, in that all-important Flaubertian surface, too little is put into investigating, much less mining, the rich lode of human possibility. The irony, of course, is that our "new fiction" ends up as mannered and conventional as the bourgeois realism it purports to surpass.

I mention all this not to dismiss Boyle as a party hack. Boyle is a writer of considerable talent, a finished craftsman. But I would like to see him push beyond this game of pure craft into a more difficult realm, where experience, understanding, and vision must serve in the shaping of something new.