THE TRADITION-BOUND Bostonian remembered in The Late George Apley once said of himself: "I am the sort of man I am, because environment prevented my being anything else."

Environment -- the whole volatile business of where one's from, what one sees from a childhood bedroom window, who sits next to one in a Harvard undergraduate class -- is the essential stuff of Millicent Bell's biography of novelist John P. Marquand. Environment and heredity -- her book opens in Curzon's Mill, the idyllic Massachusetts spot which was young Marquand's personal Eden, and she proceeds to provide a genealogy of his family dating back to the 1700s. Peopled with eccentric Curzon aunts, the house in Curzon's Mill was the last bastion of the once-flourishing Marquand empire that J. P. Marquand's father managed to lose summarily in the stock market crash of 1907.

Bell makes much of the writer's early years, devoting full, detailed chapters to his high-school days (they were gloomy), his Harvard undergraduate days (these were better, thanks to the Harvard Lampoon, even though the future Pulitzer winner made neither the staff of the Crimson nor the prestigious Signet Society), and his tenure on the Boston Evening Transcript. Bell's research is prodigious: the book is studded with small detail, anecdotes and facts which serve to illuminate both Marquand and the swiftly changing times in which he lived.

John P. Marquand was born in 1893; a world in which Sir Walter Scott was forbidden reading was not so very far behind him. Through his exposure to his elderly aunts, to his impressive, rather baronial grandfather (the writer was the banker's namesake), Marquand had a foot in the prosperous, self-confident world of 19th-century American life as it was lived by the upper classes. That his own life, especially his childhood, was not ringed round with such gilded certainties helped make him the writer he was. In The Late George Apley, Wickford Point, H. M. Pulham, Esquire and other, later novels, he turns again and again to the world of business, of upperclass New Englanders trying to maintain standards (and not touch capital) in the uncertain 20th-century world that is beginning to unfold. He does it with an ironic detachment, that makes the satire that much more effective. The novels are the books of a man who was, as Bell demonstrates, of that world, but never really in it.

Marquand was a grand success as a writer, as a public persona gifted with a sharp and funny tongue, as a man who returned to his childhood home and practically bought the whole town and environs. "Yet," Millicent Bell believes, "because we carry a theater within us where all the struggles of youth continue to repeat themselves, the drama of Marquand's earlier life never stopped . . . The suspicion of condescension, the sore sense of a lost title that he must somehow reclaim by his own efforts -- all this would translate itself to other scenes."

In 1936 Marquand did three rather important things: he fell in love with Adelaide Hooker, who would become his second wife; he bought a house not far from Curzon's Mill; and he finished The Late George Apley. Marquand's study of what Bell terms "the world he both loved and resented" appeared to rather snappish reviews in Boston.

The Evening Transcript reviewer faulted Marquand's spelling of the Berkley Club as "unknown either in Boston or London." But Apley sold, and it sold everywhere. Then came the Pulitzer, and Marquand at last achieved the hero's homecoming that Bell convincingly argues he had been looking for all his life.

From here on in, Marquand lives the life of a public man, writing, living at his Kent's Island estate, acting as an overseer for Harvard. Things fall apart within: divorce, disruption with children, battles of various sorts. But at the end, this American life seems to achieve a kind of shapeliness, marked by gestures of reconciliation. One of his last acts before an enviably quiet death is the bequeathing of his professional correspondence to Harvard's Houghton Library. (His manuscripts had gone to Yale in 1950, after that university gave him an honorary doctorate. In a typically acerbic note to Harvard, he had written, "Seeing that Yale honored me last year with a Doctor's Degree, I should prefer having my papers end up there rather than at my alma mater Harvard, which takes a dimmer view than Yale regarding my abilities.")

In The Late George Apley, Marquand's narrator Horatio Willing writes of Apley's letters: "Collectively they reveal the spirit of the man and his influence on the life around him. They reveal too, I think, the true spirit of our city and of our time, since Apley was so essentially a part of both."

Taken as a definition of the biographer's task, Willing's expatiation applies nicely to what Millicent Bell has accomplished for John Phillips Marquand.