HOUSTON (NYTimes) - Len Wein, a prolific comic book writer who collaborated on bringing to life two of the art form's best-known characters, Wolverine and Swamp Thing, died on Sunday in Los Angeles. He was 69.

His wife said he had been struggling with heart problems and other ailments.

In a career spanning almost a half-century, Wein wrote for Batman, the Flash, Superman, the Justice League Of America and numerous other comics series.

He was also an editor, perhaps most notably on DC's pivotal Watchmen series in the 1980s. He had writing credits on numerous television shows, many of them based on characters he had helped create.

"I first met him in 2008," Hugh Jackman, who played Wolverine in films, said on Sunday on Twitter. "I told him - from his heart, mind & hands came the greatest characters in comics."

Leonard Norman Wein was born on June 12, 1948, in New York. By the time he received an art degree at Farmingdale State College, he was already known around the DC Comics offices in New York.

He and his friend Marv Wolfman had begun turning up for the regular tours of those offices as teenagers.

Wein was aiming to become an artist until someone at DC, assessing his offerings, told him, "I don't think the art's quite there, but I kind of like these stories".

He and Wolfman sold their first work to DC in 1968.

Wein found success relatively quickly when he and artist Bernie Wrightson created Swamp Thing, who first appeared in 1971.

The humanoid, plant-like superhero made a strong impression, especially on others who were writing comics or aspired to.

In 1975, Wein joined artist David Cockrum to relaunch Marvel Comics' X-Men, the team of mutant superheroes created in 1963 by Stan Lee and Jack Kirby.

Wein and Cockrum created new characters, including Storm, Nightcrawler and Colossus.

Wolverine, who first appeared in an Incredible Hulk story Wein wrote, also joined the X-Men universe, which yielded not only many comics but also a profitable series of movies.