This year’s National Book Award winner for nonfiction also deals with the mystery and secrets of an extended family, and with their repercussions over time. Beginning in 1698 and continuing for the next 167 years, the Balls of South Carolina, whose numerous rice plantations stretched along the Cooper River, north of Charleston, were among the most prosperous families in the Old South. But their wealth, comfort, status, and power were made possible only by the almost 4,000 black people who worked their land. In Slaves in the Family, Edward Ball has examined — in mind-boggling detail — his forebears’ grim slave-owning past and tracked down living descendants, both black and white. ”I felt accountable for what had happened,” he writes, ”called on to try to explain it.”

Strangely, this is a book that promises to be far more compelling than it turns out to be. For one thing, Ball himself remains remote, a dispassionate collector of archival information and tape recordings. His cross-country trips locating, then talking to, the multi-great-grandsons and great-granddaughters of his family’s slaves are narrated with monotony and thudding prose. But even more of a problem, the inter-chapters that deal with plantation life in the 18th and 19th centuries are crammed so full of genealogy that after a while they become drone-like, a buzz of begets and begats. Still, the story that Ball tells is the great American tragedy, and even when it’s told as ponderously as it is here, the story itself — sordid, amazing, disgusting, infuriating — is always worth hearing again. B