With "World War Z" pulling in big numbers at theaters and "The Walking Dead" returning for a fourth season on AMC in October, it's easy to overlook the medium that incubated the zombie phenomenon: comic books.

The zombie as a concept arose in West Africa, and shambled from there to the Caribbean through the slave trade, where it was folded — along with other West Africa religious concepts and rituals, Caribbean faiths and Roman Catholicism — into what we call voodoo. And for a long time, virtually any story involving zombies was set in Haiti or otherwise involved voodoo.

Take, for example, "White Zombie," the 1932 Bela Lugosi movie, which is considered the vehicle by which "zombies" as a word and a concept entered the popular imagination. It was set in Haiti, where a native witch doctor turned a beautiful blonde into a zombie for nefarious reasons.

"White Zombie" was released during the same era that gave us "Frankenstein" and "Dracula" (1931), "The Mummy" (1932), "King Kong" (1933) and "The Wolf Man" (1941). But while those classic monsters became popular enough to become virtual genres unto themselves, the zombie languished in his or her grave.

But while zombies lay unmoving on screen, they lived on — or un-lived on, I guess — in comics. Until the Comics Code of 1954 decapitated the horror genre, there were zombies galore in comics with titles like "Skeleton Hand," "Strange Tales" and "Forbidden Worlds." Those stories sometimes used the Haiti connection, and sometimes didn't, and quite often made very little sense at all.

Yes, there were also vampires, werewolves, giant apes, ghouls and every other conceivable kind of monster in pre-Code horror comics. But that was true of movies, books and TV, as well, which seemed to use everything except zombies. So if you wanted to sink your teeth into a zombie story before 1954, you pretty much had to read comics.

The grand-daddy of the zombie wave in comics was "The Walking Dead." Writer Kirkman, a longtime zombie-movie fan, had always wondered what happened in zombie-apocalypse movies after the credits rolled, and set about writing it in a black-and-white comic book with a tiny press run in 2003. Apparently a lot of readers wondered the same thing, because "The Walking Dead" exploded. "TWD" has almost become its own industry, dominating the graphic-novel sales charts, giving AMC its biggest hit and launching a jillion apocalypse stories, both in comics and on TV, with zombies and without.

But comics alone didn't keep the zombie alive. Or un-alive. Credit where it's due: The zombie would still be a niche monster if it hadn't been for director George Romero. His 1968 black-and-white movie, "Night of the Living Dead," separated the zombie from Haiti, giving it a new origin as a creature that can spontaneously occur anywhere, usually from some sort of unexplained pandemic. He also gave academics something to chew on, by using the zombie as a metaphor for social ills.