Du Pont Dynasty: Behind the Nylon Curtain by Gerard Colby (Lyle Stuart: $18.95) In the 10 years since this biography first appeared, the Du Ponts have been very active. And Gerard Colby has been right behind them. Daunting for its size (900 pages), as much as for the sheer weight of information presented, Colby traces the world's largest family fortune from the arrival of Irenee Du Pont in 1800 to the 1980s. And, he does a good job of staying within the reach of his thesis: that the Du Pont fortune is in some ways unique to American experience; in other ways, it is the American experience. Colby doesn't like the influence that the Du Pont family wields and that comes through on almost every page. That aside, he gives us an important perspective on American history through analyzing the fate of one of its major industrial families.