httpss://www.youtube.com/watch?v=Ru1d1z8wVc0

In 1974, with the Vietnam War in its final stages after American military involvement had all but ended, Mr. Hayden and Ms. Fonda, who were married by then, traveled across Vietnam, talking to people about their lives after years of war, and produced a documentary film, “Introduction to the Enemy.” Detractors labeled it Communist propaganda, but Nora Sayre, reviewing it for The New York Times, called it a “Pensive and moving film.”

Thomas Emmet Hayden was born in Royal Oak, Mich., on Dec. 11, 1939, the only child of John Hayden, an accountant, and the former Genevieve Garity, both Irish Catholics.

Along with his wife, Mr. Hayden is survived by the three children as well as two grandchildren and a sister, Mary Frey.Mr. Hayden joined the Freedom Riders on interstate buses in the South in 1961, challenging the authorities who had refused to enforce the Supreme Court’s rulings banning segregation on public buses.

In 1968, Mr. Hayden helped plan antiwar protests in Chicago to coincide with the Democratic National Convention.

Although Ms. Fonda was a wealthy movie star and financially supported Mr. Hayden’s early political career, she and Mr. Hayden lived for years in a modest home in Santa Monica, near the ocean but not on it.

Mr. Hayden wrote more than 20 books, including several memoirs, re-examinations of the civil rights and antiwar movements, and volumes on street gangs, Vietnam, his own Irish heritage, the environment and the future of the United States.

Besides troves on civil rights and antiwar activities, they included 22,000 pages of F.B.I. files amassed in a 16-year surveillance of Mr. Hayden.