Best-selling author Peter Maas, who chronicled the Mafia from informants Joe Valachi through Sammy "The Bull" Gravano during a prolific 50-year career, died Aug. 23. He was 72.

Mr. Maas, who detailed the life of an incorruptible New York City police officer named Frank Serpico in a book that became an Al Pacino movie, died at Mount Sinai Hospital of an undisclosed cause, said Lucille Lee, a hospital spokeswoman.

Mr. Maas wrote more than a dozen novels and nonfiction books, along with an assortment of investigative magazine pieces. He also had written for New York magazine, the Saturday Evening Post, Look and Collier's, among others.

He considered himself part of the "new journalism" with fellow writers Jimmy Breslin and Tom Wolfe, bringing the flourishes of fiction writing to news stories during the early 1960s.

In 1969, Mr. Maas wrote "The Valachi Papers," his account of mob soldier Joe Valachi's brutal career and decision to become a federal informant. Valachi's 1963 testimony before a congressional panel thrust the mob into the national spotlight. Mr. Maas's book became an international bestseller and a hit movie.

More than 30 years later, Mr. Maas collaborated with a latter-day Valachi: Gambino family underboss Sammy "The Bull" Gravano, whose testimony landed John Gotti behind bars for life. "Underboss: Sammy the Bull Gravano's Story of Life in the Mafia" became a New York Times No. 1 bestseller.

Peter Maas wrote more than a dozen novels and nonfiction books as well as many magazine articles.