THE GRAPHIC NOVEL — whose secret identity is a lengthy comic book — has grown up.

Why? The appeal of graphic novels now stretches well beyond these books' traditional market of teenagers and 20-something males.

The popularity has surfaced in movie theaters. Films such as "X-Men," "30 Days of Night," "Sin City," and "The 300" all had their origins in graphic novels, regular comic books, or both.

As a result, video games and other hot gifts will have to make room under the Christmas tree for these complex comic books.

"They are not just for kids, they are for all ages," said Mike Cresser, owner of Crush Comics in Castro Valley. "They are for males and females. A graphic novel is something that attracts all readers. Just because it's a comic book or based on a comic doesn't reduce its appeal."

Recent sales trends back up suggestions that graphic novels are more popular than they were a few years ago, according to data released by ICv2, a Madison, Wis.-based company that tracks popular culture.

Graphic novels in 2006 generated $330 million in sales in the United States and Canada. That was up 12 percent from $295 million in graphic novel sales in 2005.

Sales of periodical comic books — the kind that usually ship once a month andinclude familiar titles such as "Uncanny X-Men," "Batman," "Buffy the Vampire Slayer," and "Witchblade" — totaled $310 million in 2006, up 15 percent from 2005.

"Do we see more women and more girls getting into comics? Yes, more so than we ever have," said Joe Field, owner of Flying Colors Comics in Concord. "Graphic novels and other comics are driving a lot of fans of all ages into comics shops to get the next dose of their favorite characters."

In many cases, these illustrated novels, which once were called trade paperbacks, compile a series of previously published comic books that together told a complete story. That way, people who might have missed some or all of the original monthly titles could still get find out what happened.

Compilations often include extra goodies such as an artist's original sketches, which mirrors the kinds of bonus features included in a new DVD.

The resurgence of graphic novels in particular, and comics in general, have bolstered artists around the nation, including some who live and work in the East Bay.

"Comics have historically been a disparaged art form," said Gene Yang, a Fremont resident who draws and writes graphic novels. "People did not look on comics very highly. They were seen as a disposable medium. But over the last three or four years, comics have really picked up."

In some cases, graphic novels tell tales set in a more mundane world than fantasy settings inhabited by Bruce Wayne, Clark Kent, or Buffy Summers.

"Comics that were about super heroes and nothing else are now about a wide range of stuff," Field said.

Yang's books include "American-Born Chinese," which tells the story of a Chinese American boy who grows up in a neighborhood primarily inhabited by whites.

Writers of graphic novels increasingly use the Internet to tell their stories. Tim Ferreira, a Livermore resident, posts his novels on the Web. He also attends comic book conventions to sell his stories to print publishers.

"The nice thing about graphic novels is they are complete stories," Ferreira said. "They have a beginning, a middle, and an end."

Japanese comics, called manga, have become a key propellant behind the graphic novel's broader appeal in the U. S., said Milton Griepp, publisher of ICv2, a Web site that tracks trends in popular culture. Manga books are often written as full-length illustrated novels and tackle as wide a range of topics as standard novels.

"Manga has brought in many female readers," Griepp said. "Because of the popularity of manga, more females are reading graphic novels."

Graphic novels also have strong links to widely popular movies or current TV shows. Those connections can produce a new crop of readers.

The feature-length films "The 300" and "Sin City" were based on graphic novels of the same title. The ''Sin City" graphic novel itself was based on a series of periodic comic books. A proposed movie called "The Watchmen" is based on comic books and graphic novels.

The "Heroes" TV series has a graphic novel that is selling well. Other hot TV-linked items are periodic comics and graphic novels that purport to present the eighth season of "Buffy the Vampire Slayer," a cult hit that ended after seven seasons.

The recent trends mean graphic novels can make great gifts this year.

"They are definitely more popular this Christmas," Cresser said. "People come into the store with a list from friends and relatives who want graphic novels as a gift."

George Avalos covers jobs, economic development, commercial real estate, finance and petroleum. Reach him at 925-977-8477 or gavalos@bayareanewsgroup.com.