A Harvard-educated historian and author whose work focused on the American Revolution and the U.S. Colonial period, he was a two-time recipient of the Pulitzer Prize for history.
He attended Williams College and Harvard University. One of his early scholarly works, The New England Merchants in the Seventeenth Century, was published in 1955.
His best-known works include The Ideological Origins of the American Revolution (1967) and Voyagers to the West: A Passage in the Peopling of America on the Eve of the Revolution (1986). He was one of two authors of the American history textbook The Great Republic.
He was born in Hartford, Connecticut. He later settled in Boston, Massachusetts, where he taught at Harvard.
He and William Prescott are both well-known historians.