THE ENGLISHMAN’S BOY.<i> By Guy Vanderhaeghe</i> .<i> Picador USA: 336 pp., $24</i>

These days, if you want to make a movie with true old New York atmosphere, New York is not the place to shoot. For authenticity, Toronto is your location (Martin Scorsese went there for “The Age of Innocence”). Much of Canada is, after all, just like the United States, only more so. America on Prozac. Oh, Canada. It’s up there, hanging over us, big and bland, the north of North America.

Canadian history runs parallel to ours, of course. But its wild west was bigger, emptier, probably wilder. Horse thieves and murderers on the run in the United States were beyond the law once they crossed its northern boundary. In more recent times, in the Vietnam years, not only did American men avoid military service by fleeing to Canada, but the proximity of that alternate America was also a comfort to thousands who didn’t cross the border but knew they could.

Guy Vanderhaeghe, who hails from Saskatoon (and won his second Governor General’s Award, a major Canadian literary prize, for this novel), has staked a claim under the big skies on both sides of that border, and he has worked the territory well. An epic tale that brings together the American West before the turn of the century with the Hollywood of the 1920s, “The Englishman’s Boy,” though far from perfect, is nearly a great (North) American novel.

It’s 1923, and Damon Ira Chance is a megalomaniacal Hollywood studio head reminiscent of Howard Hughes. A reclusive eccentric, Chance wants “to make pictures rooted in American history and American experience” that will surpass the work of his hero, D.W. Griffith. “Griffith is the man who has given America to Americans,” Chance believes. “America had cried out for bread and received stones until Griffith came along. It was he who had answered the cry for bread with bread, filled America’s spiritual emptiness with a vision of itself.”

Griffith’s great Civil War epic, “The Birth of a Nation,” according to Chance, was an American “Iliad,” and the genius of that film lay in Griffith’s decision to advertise that motion picture as fact. “Americans are a practical people, they like facts. . . . The average American feels foolish when he enjoys a made-up story, feels sheepish, childish, a mooner, a dreamer. But entertain him with facts and you give him permission to enjoy himself without guilt. . . . He prefers to feel virtuous because he’s learned something useful, informed himself, improved himself. . . . Facts are the bread America wants to eat. The poetry of facts is the poetry of the American soul.”

Chance confides these beliefs to the novel’s narrator, Harry Vincent, a young Canadian from Saskatoon struggling to earn a living in the script department at Best Chance Pictures. Chance wants something from Harry, and he’s willing to pay him well for it. He wants Harry to get the story, the facts, of the life of one Shorty McAdoo, a grizzled cowboy who has played occasional bit parts in westerns. McAdoo’s story will provide Chance with the material to make the Great American Picture, “the American ‘Odyssey.’ ”

Woven through the novel is a parallel story that gives the book its title, told in chapters set in the American Northwest in the 1870s. Never named in these pages, the 17-year-old gun bearer for an Englishman on a hunting trip is suddenly stranded when his employer dies in an isolated frontier town in the Montana territory.

The Englishman’s boy has “the gaunt, cadaverous look of the rural poor,” with “anthracite eyes” that “did his talking for him.” He gets into trouble quickly, and his best survival option seems to be joining up with a rough band of wolf hunters who have just been robbed of 20 horses by Assiniboin Indians headed north. The wolfers follow them into Canada on a doomed mission of retribution. Before long, readers will conclude that the Englishman’s boy is Shorty McAdoo.

Vanderhaeghe’s writing flows spectacularly when he describes the Montana territory: “The heat of the previous day had eased a little, but the wind had struck up fierce, gusty. As far as the eye could see, the short curly grass writhed and shuddered under the invisible lash of the shrilling wind. The Englishman’s boy rode leaning into it, like a man shouldering through swinging doors, his bowler hat battened down tight around his ears. Handfuls of sparse, somber cloud sped overhead, spinning shadows on the glowing, rolling grass like coins tossed carelessly across the lamplit baize of a saloon table.”

More problematic is his rendering of the 1923 segments of the novel. The evidence of much diligent research is all too clear, even before the acknowledgments page, which lists six sources of Hollywood history and lore, but it remains on the surface of the narrative. On the other hand, the six sources cited for Western history have been much better metabolized. The details based on the actual Cypress Hill Massacre, a significant event in Saskatoon history and in this novel, inform the 19th century passages with the poetry of facts.

In the Hollywood narrative, when the writing stays in the moment, it is superb, as in this scene in which Harry tries to get Shorty to teach him how to shoot: “I raise the gun. Immensely heavy, a great weight dragging on my arm, it is as if I am trying to lift the scarecrow staked in the garden on the tip of the gun barrel, uproot it from the earth. I fire, the pistol springs in my hand, a small captive animal struggling in my fist.”

But some of the Hollywood scenes are burdened by a heavy freight of meaning and messages. Rachel Gold, Harry Vincent’s love interest, is a hard-drinking, ambitious, fun-loving, smart Jewish scriptwriter. But she is never quite fully developed as a character and seems to exist chiefly to explain the Big Ideas, which she does in long speeches about cronyism in the film studios, Hollywood anti-Semitism, the hypocrisy of Hays censorship and the amorality of it all.

“Do you think anyone in this room has even considered they might have to give this up?” Rachel asks Harry over dinner in one of her rhetorical rants. “Even entertained the notion? I started in movies because they were fun. They’re not fun anymore and I’m still here. Why? Because I got used to good clothes, money, fame of a sort. But I liked it better when we wrote a scenario Tuesday, filmed it on Wednesday.”

Rachel’s relationship with Harry’s mother isn’t particularly convincing either. (Harry’s mother too is mostly a device, a person he must support financially, to explain his motivation for doing Chance’s bidding, although he must deceive McAdoo to get his story.) Ultimately, Rachel comes across like a vivacious Sammy Glick played by Judy Holliday.

Despite the occasional clumsiness, “The Englishman’s Boy” is essentially such a good idea that each segue from past to present to past again is a graceful little leap between subtly matched gestures and images. Vanderhaeghe has brought together two familiar and essentially American settings and linked them in an imaginative and surprising way with his outsider’s sensibility. His novel tells us the American frontier story in our own vernacular; it is hard to refrain from invoking “The Day of the Locust” when considering how the novel ends, just as it is inevitable that both “Lonesome Dove” and “All the Pretty Horses” come to mind when one savors the chapters set in the Montana territory.

“Why is a Canadian so concerned about teaching Americans how to be American?” Rachel asks Harry when he tries to explain his work for Chance. “Canada isn’t a country at all,” his reply begins. “It’s simply geography.”