JOHN GREGORY DUNNE, novelist, screenwriter and husband of fellow author Joan Didion, died Tuesday of a heart attack at age 71. Newsday reports:

The grandson of an Irish immigrant, he often focused on the Irish-American experience--particularly in his million-selling novel "True Confessions." The 1977 breakthrough book involved a Los Angeles murder and its effect on two Irish-Catholic brothers, one a police detective and the other a priest.

Robert De Niro and Robert Duvall starred in the movie, which Dunne adapted with Didion.

"'True Confessions' was a major novel, one of the best books ever written about politics," said Pulitzer Prize winner David Halberstam, a friend and fellow writer. "He was a very important writer, and a wonderful friend--talented, edgy, combative."

Dunne's book "The Studio" provided an unflinching look behind the machinations at Twentieth Century Fox, a major motion picture studio. It was hailed for its insider's take on Hollywood.

Dunne eventually became part of the movie industry, working with Didion on several screenplays. Their first, "Panic in Needle Park," starred Al Pacino and captured an award at the 1971 Cannes Film Festival.