LOS ANGELES -- In a harrowing 2002 book, Jonathan Aurthur chronicled his son Charley's long struggle with mental illness and his suicidal leap, at 23, into the morning rush-hour traffic on the Santa Monica Freeway.
Eleven days after Charley's death on Nov. 1, 1996, Mr. Aurthur visited the overpass, peered down at the traffic and walked away feeling oddly liberated. ''[Charley's] terrible affliction and suffering had imprisoned him but it had also imprisoned me," he wrote, ''and now both of us were free."
Mr. Aurthur did not remain free, however. The longtime wetlands advocate, who friends said was despondent over mounting debt, his son's suicide, and the reelection of President Bush, leaped to his death from a 500-foot cliff in Angeles National Forest. A search-and-rescue team found the body Nov. 29, after he had been missing since Nov. 22. He was 56.
Friends called it a tragic, unexpected end for a complex man who had spent years grappling with his son's death and advocating treatment for depressed young people.
''It's just so shocking," said Jennifer Lewis, a longtime family friend who had dated Charley and remained friends with his family. ''He studied [suicide] extensively. He knew all the statistics. It was a very big interest to him, deep and profound."
Mr. Aurthur was highly intellectual, Lewis said, although he never completed college. He was also physical, working out for hours at Gold's Gym in Venice. Friends described him as a go-getter who injected himself into the cause of restoring wetlands near a development he had heatedly opposed.
Despite his outgoing activism, friends said, Mr. Aurthur carried the burden of his son's death and his inability, in the end, to save him.
An intelligent, handsome young man who played piano and wrote poetry, Charley was 18 when he experienced his first psychotic episode while on a camping trip to Yosemite after his freshman year of college. Driving home on a mountain road, he closed his eyes and took his hands off the wheel of the family car -- in an effort, he would later say, to hand himself over completely to a ''god consciousness."
The car flipped over twice and landed in a ditch, totaled, but Charley walked away without a scratch. Three years later, he stabbed himself in the heart with a Swiss army knife, but again miraculously survived. Twice he attempted suicide by taking pills and slashing his wrists.
After Charley jumped to his death, Mr. Aurthur quit working as a copy editor and proofreader for a trade magazine publisher to research a book, ''The Angel and the Dragon: A Father's Search for Answers to His Son's Mental Illness and Suicide," published in 2002. In it, he revealed the family's efforts to find the right treatment for the troubled young man, and he quoted many of the thoughts and poems from the 10 spiral notebooks that made up Charley's record of adolescence and young adulthood.
''No one was able to help him bolster his internal resources and counterattack," Mr. Aurthur wrote, ''so finally, I think, he may have seen that the only way to gain control over a life in which he had become a mere spectator was to end it."
Mr. Aurthur attended St. John's College in Annapolis, Md., and the University of California, Los Angeles, where he studied film.
From the late 1960s through the early 1980s, he worked as a community organizer and documentary filmmaker. His former wife, Elinor, said they met in 1969 at a planning meeting for a group seeking to prevent the overdevelopment of Venice. Together, they got involved in Los Angeles Newsreel, a group that produced and showed political documentary films about the Black Panthers, Vietnam, and Cuba.
Known for his leftist leanings, Mr. Aurthur also edited a journal of political theory called Appeal to Reason and wrote a book on political economy called ''Socialism in the Soviet Union."
He leaves a daughter, Jenny; a brother, Tim; and two sisters, Gretchen and Kate.