SO HERE we have Henderson Dores. He is 39 years old, English, a bit on the timid side, not terribly sure of himself and not so happy with himself into the bargain. He's come to New York, where he works as the "Impressionist man" for a small art gallery that has hired him "to get things moving, whip up some trade, start making a name for the firm." But neither art nor career is the real explanation for his move; he has left Britain "in a conscious and deliberate flight from shyness," has "come to America for the cure" because "here, shyness was banned; shyness was outlawed, prohibited." Everywhere he goes he sees new evidence of it, as when he goes out for lunch with an American colleague:

"They walked down some steps into a pale-honey and lime-green restaurant. The bar area at the front was full of brilliant women and tall, broad-shouldered men. Everyone spoke in loud firm voices and seemed laughingly at ease. Sadly, as he knew it would, Henderson felt his own confidence begin to ebb away. There must be some law of Newtonian physics to explain this phenomenon, he considered; something about the power of a superior force to sap and drain energy from an inferior one of the same type. He looked about him at the fabulous lunchers. Pruitt shouted clear strong welcomes to people he knew. I want to be like you lot, Henderson thought, as he felt his shoulders round and his chest concave; I want your confidence and purpose, I want your teeth and tans, he pleaded, stepping out of the way and apologizing to a waiter. It's not fair."

Indeed it is not, and it does not get any fairer as Henderson Dores stumbles his way through Stars and Bars, which is in every respect a thoroughly accomplished and beguiling piece of work. Like William Boyd's first novel, A Good Man in Africa, his third is comic in tone and intent; though it is not without its serious aspects, there is in it none of the darkness to be found in his previous novel, An Ice-Cream War. Yet though Boyd returns here to comedy, it is with a considerably surer hand than in A Good Man in Africa, the hilarity of which is thrown somewhat off track by an unexpectedly sombre conclusion; in Stars and Bars Boyd has a more confident hand on his material, with the happy result that the novel's serious side emerges naturally and unobtrusively from the comedy that is its essence.

And comic it most certainly is. By way of introducing Dores to America -- "This is his problem: he loves America, but will America love him back?" -- Boyd quickly moves him out of Manhattan and into the distant South. He goes there, to an inland hamlet mysteriously called Luxora Beach, in order to assess the paintings owned by one Looms Gage, a "reclusive, Southern millionaire" who has "a small but very select collection." A handful of the paintings in it, the gallery hopes, will do sufficiently well at auction to establish the firm's reputation and thus lead to expanded business; it is with a heavy weight on his shoulders, therefore, that Dores heads to Dixie.

HE HEADS there with dangerous company: Bryant Wax, the nymphetic 14-year-old daughter of his former wife, Melissa, who has divorced her second husband and is now entertaining the possibility of remarrying Dores, though not to the extent of permitting "pre- remarital sex." This helps explain why Dores has involved himself, on the side, with the aggressive Irene Stein, even though in saner moments he cannot imagine why he is flitting uncertainly from one woman to another, tangling himself in a web of deception that only promises to get more messy now that he has Bryant on his hands. Melissa thinks a Southern excursion will be good for her darling daughter; it certainly proves to be no good for poor Dores, her reluctant chauffeur and chaperon.

Arriving at Luxora Beach after an unsettling drive with Bryant, Dores finds himself in enough fixes to keep any comic novel percolating for hours. Loomis Gage turns out to be a spry octogenarian who is oddly reluctant to let Dores see the paintings; his elder son, Freeman, is a hulking lout who warns Dores, in most emphatic language, not to try to sell the paintings and, for that matter, to be off the premises within 24 hours; Cora Gage, the master's only daughter, is a raving Anglophobiac, and his younger son, Beckman, indulges himself in hallucinations about Vietnam; Bryant decides that she has fallen in love with Duane, "a 34-year-old layabout with a liking for loud music and a chronic incapacity to fix cars"; a couple of rival art dealers, more closely resembling Mafiosi, show up and attempt to establish their own claims to the Gage collection.

"Out here he felt weak and unprotected, alien and unfamiliar," Dores quickly realizes. This "America" by which he has hoped to be liberated turns out to be a far more complex and difficult place than he had bargained for: "He was beginning to feel unable to cope. The struggle to fit his personality to his new environment, to emulsify with his chosen culture like oil and vinegar, just wasn't happening. It was too unyielding; he and America just weren't creating the harmony he had expected. It simply wasn't enough, clearly, to be keen, to wish earnestly for something to happen. Perhaps all marriages were made in heaven, he thought glumly. He had an awful foreboding nothing was going to work out."

Which is why soon enough he finds himself skulking around New York in darkest night, clad in nothing save a cardboard carton that once had held 2,000 "Marymount No-Slak Sanitary Napkins." But how he gets there, and what he learns from it all, are not to be disclosed herein. Suffice it to say that along the way Boyd stages several splendid set- pieces, among the most memorable of which are a dinner at the Gage mansion during which Dores becomes miserably sloshed on a potent local brew called Henry's Goat, and a disastrous weekend stay in Atlanta at the Monopark 500 Hotel, a daunting example of "this new breed of American hotel -- the hotel as wonderland, as secular cathedral, as theme park." It is during this weekend that Dores' relationship with the stormy Irene reaches a climax, though not exactly the one Dores had in mind.

All of this is so funny that it's easy to lose sight of the skill with which Boyd has brought it off. He is an Englishman who has spent precious little time in the United States, yet he recreates American speech with the aplomb of a born mimic -- I did not detect a single false phrase or inflection -- and he has got the American landscape, both physical and psychological, exactly right. Beyond that, and of far greater importance to the book's success as a work of fiction, he has populated it with people so convincingly real that even when the action borders on the fantastic, the reader never loses the sense of being in an entirely human world, one that seems familiar even when it seems bizarre. Rich though the comedy is, it never once lapses into excess; this, as much as anything else, keeps the novel within its human scale.

With four books -- the three novels plus The Yankee Station, a collection of remarkably diverse, surprising short stories -- Boyd has firmly established himself as a writer of impressive, original achievement. He writes more often than not about the conflict of alien cultures, but he invariably does so in ways that are unpredictable and imaginative; he is heir to an established tradition of English comic fiction, yet within it he is clearly his own man; he is a biting satirist and social commentator, yet he regards his characters with an affection that is too rare in such fiction. There's hardly a writer around whose work offers more pleasure and satisfaction.