Midwestern farm country has proved fertile soil for fiction writers, and no one, perhaps, has cultivated it to such fine effect as Jane Smiley, in works ranging from her Pulitzer-Prize-winning "A Thousand Acres" to "Moo," her comedy of agricultural academia. Another persistent interest of Smiley's, made explicit in her novel "The Greenlanders" and her preface to "The Sagas of the Icelanders," is the Norse saga, her long-ago subject of study at the University of Iowa.

This new novel, the first in a projected trilogy, brings these strains together to make of Smiley's Balzacian project — which has traveled across the country's generations, geography and milieus — the saga of the American family sprung from immigrant stock rooted in rich Iowa farmland.

Beginning in 1920 and proceeding through yearly chapters to 1953, "Some Luck" follows the family that starts with the marriage of Walter Langdon ("a bastard mix, as his grandfather would say") and Rosanna, product of Augsbergers and Vogels (blonde, but so slender and perfectly graceful, "you didn't think she'd been raised on a farm, had farms all through her background, even in Germany").

Through vignettes focusing on alternate members of the family — Walter and Rosanna, their many children as they appear and mature and start families of their own, and Rosanna's sister, Eloise — the book takes us through major events and developments of the first half of the 20th century as intimate moments and individual experiences and observations.

There's schooling in Chicago and at Iowa State (and the University of Iowa, where one son, Henry, studies medieval literature and language, much like Smiley herself), the drought and the Depression as felt on a farm, experiments in munitions and fertilizer, the war in Italy and France, the Red Scare and the Soviet threat, and plenty on learning about farming, homemaking, love and work — even a little on spying, horse racing and real estate.

Smiley's range is, as ever, remarkable, as she inhabits the heroic firstborn, the diffident little brother, the angelic girl, the bookish boy, the afterthought, always managing to convey the specific nature of each character's experience even as her narrative seems to balance birth order as fate against character as destiny, with each child's lot very much determined by what has happened so far in the family, but also inescapably a function of immutable character.

These moments, though, however closely observed, generally don't achieve the power or poignancy of similar instances in Smiley's novels and stories that are more deeply immersed in particular characters' points of view. (Compare, for instance, the pain of the boy Joe here, when the father shoots the stray dog he's become attached to and drowns her puppies, with that of the boy forced to participate in the slaughtering of the lamb in Smiley's novella "Good Will.") And yet, what's sacrificed in depth is more than made up for in breadth, as the cumulative experiences of these people, all depicted with such convincing care and detail, convey a sense of the relations that create a world.

Ellen Akins teaches at the low-residency MFA program at Fairleigh Dickinson University. She lives in Wisconsin.