Associated Press Harvey Pekar.

Harvey Pekar, a comic book author whose titles chronicled a life of everyday humor and frustration, was found dead early this morning at his home in Cleveland, according to Cleveland.com. He was 70.

Even if you weren’t familiar with his American Splendor comic books – graphic novels, really – if you were aware of pop culture in the 1980s, the you knew about Pekar. He was a frequent, irascible guest Late Night with David Letterman on NBC. His life was later the subject of an award-winning film, American Splendor.

From the Cleveland.com obit:

“American Splendor” carried the subtitle, “From Off the Streets of Cleveland,” and just like Superman, the other comic book hero born in Cleveland, Pekar wore something of a disguise. He never stepped into a phone booth to change, but underneath his persona of aggravated, disaffected file clerk, he was an erudite book and jazz critic, and a writer of short stories that many observers compared to Chekhov, despite their comic-book form.

Unlike the superheroes who ordinarily inhabit the pages of comic books, Pekar could not leap tall buildings in a single bound, nor move faster than a speeding bullet. Yet his comics suggested a different sort of heroism: The working-class, everyman heroics of simply making it through another day, with soul — if not dignity — intact.

Pekar began writing American Splendor in the early 1970s. He befriended counterculture cartoonist R. Crumb, who did the illustrations for the earliest issues of the books.

Pekar’s quirky personality, along with the edgy humor in the comic books, drew the attention of Letterman, who made Pekar a frequent guest in the late 1980s. Their exchanges were often contentious, but made for great television.

American Splendor was made into a 2003 film starring Paul Giamatti as Pekar. It won the Grand Jury Prize at the Sundance Film Festival that year, and was nominated for an Academy Award for Best Writing, Adapted Screenplay.