Håkan Söderström, the hulking hero of Hernán Diaz’s novel, “In the Distance,” makes a stupendous entrance, ascending onto the first page through a star-shaped void on a featureless plain of white sea ice. Longhaired, white-bearded, gnarled and naked, he pulls himself onto the floe and walks on bow legs to an icebound schooner, carrying a rifle and ax. We are somewhere, nowhere, in the frozen north.

Nowhere is also the place “In the Distance,” Mr. Diaz’s first novel, seems to have erupted from. He had no agent when he answered an open call for manuscripts by the nonprofit Coffee House Press in Minneapolis, which published the novel last October. In April Mr. Diaz was named a finalist for the Pulitzer Prize and the PEN/Faulkner Award for Fiction, causing book reviewers around the country to say, who?

Mr. Diaz is a scholar at Columbia University who grew up in Argentina and Sweden, studied in London and New York and lives in Brooklyn. His book is about an immigrant Swede of unusual size journeying in America’s desert frontier between the Gold Rush and the Civil War.

Though many of its elements are familiar to the point of being worn out — saloons and wagon trains, Indians and gold prospectors — the novel is not. Mr. Diaz’s long study of North American literature, much of it steeped in the 19th century, allowed him to expertly plunder an antique genre for parts. The rebuilt mechanism is his own design, and it moves in unexpected directions: west to east, around in circles, down into the earth, and north to Alaska.