Robert W. Peterson, whose pioneering history of the Negro leagues, "Only the Ball Was White," recaptured a lost era in baseball history and a rich facet of black life in America, died Saturday at a hospital in Salisbury Township, Pa. Mr. Peterson, who lived in Lower Macungie Township, Pa., was 80.

His death was announced by his wife, Peggy, who said he had lung cancer.

When Mr. Peterson's account of black baseball was published by Prentice-Hall in 1970, little was known of the Negro leagues apart from the memories of black Americans who had been thrilled by players like Satchel Paige, Josh Gibson and Buck Leonard. Black baseball had flourished in a segregated America but was largely ignored by the mainstream press and went out of business in the 1950's, soon after the major league color barrier had been smashed.

When Mr. Peterson was growing up in Warren, Pa., he had seen some of the great Negro leaguers in barnstorming games. He later played baseball at Upsala College in East Orange, N.J., and worked as an editor for The World-Telegram and The Sun. When the paper closed in 1966, he turned to freelance writing and set out to learn the history of the Negro leagues by interviewing the star players and studying microfilm of black newspapers.

Mr. Peterson was inspired by those memories from his boyhood. In the preface to "Only the Ball Was White," he recalled: "One summer day in 1939 a kid squatted on the bank behind home plate at Russell Field in Warren, Pennsylvania, fielding foul balls (which could be redeemed for a nickel each — no small consideration in those days), and saw Josh Gibson hit the longest home run ever struck in Warren County. It was one of many impressive feats performed by touring black players that excited the wonder and admiration of that foul-ball shagger. This book is the belated fruit of his wonder."

Mr. Peterson's book traced black baseball's history from the 19th century and provided first-person accounts, brief biographies of leading players, league standings and statistics. Writing in The New York Times Book Review, Rex Lardner called the book "a worthy and fascinating addition to anyone's baseball library."

Many books on black baseball have been written in the decades since, transforming a long-neglected chapter of baseball history into a well-chronicled saga.

Mr. Peterson also wrote "Cages to Jump Shots: Pro Basketball's Early Years," "Pigskin: The Early Years of Pro Football" and "The Boy Scouts: An American Adventure."

In addition to his wife, he is survived by a son, Thomas, of Westfield, N.J.; a daughter, Margaret Peterson, of Salisbury Township, Pa.; and two grandsons.

In his memoir, "Hardball," Bowie Kuhn recalled that when he became baseball commissioner in 1969, a debate had arisen over whether to induct stars of the Negro leagues into the Hall of Fame. The Peterson book, Kuhn said, "focused greater attention on the accomplishments of Negro League players."

In 1971, Paige became the first Negro leagues star inducted into the Hall of Fame, and he has been followed by 17 others. Mr. Peterson was named to the 12-member unit that will vote Feb. 27 on the possible induction of additional figures from black baseball. In view of his failing health, he had cast a ballot in absentia.

In an epilogue in "Only the Ball Was White," Mr. Peterson called for giving full honors at Cooperstown to Negro leagues stars. "So long as the Hall of Fame is without a few of the great stars of Negro baseball," he wrote, "the notion that it represents the best in baseball is nonsense."