Somewhere between the release of Danny Boyle's zombielike "28 Days Later" in 2002 and Zack Snyder's pumped-up 2004 remake of "Dawn of the Dead," George Romero — the guy who made "Night of the Living Dead" and the original "Dawn of the Dead" — started getting a little antsy, not to mention angry.

"Here I was on the sidelines, unable to get a movie of my own off the ground, and these guys are all riffing on my work," Romero, 65, says. "I was just hoping there'd still be an appetite for zombie movies by the time I got mine made."

Unlike the undead in his movies, Romero should rest easy. The zombie genre is as healthy as it has ever been, which is good news for horror fans who like to see humans in various states of moral and physical decay.

Romero's fourth zombie movie, "Land of the Dead," opened June 24. Arriving in Austin on Friday is "Undead," an Australian import that combines zombies and aliens in a way that brings to mind previous freakish pairings, i.e. the zombies and Nazis of "Shock Waves" or the zombie who battled the great white shark in "Zombi 2."

These movies follow the success of "28 Days Later," the most recent "Dawn of the Dead" and last year's left-field zombie comedy, "Shaun of the Dead."

Why are we up to our armpits in the undead?

"People love to think about apocalypses," says Peter Dendle, author of "The Zombie Movie Encyclopedia." "If we're not talking about biblical apocalypse, then it was nuclear devastation during the Cold War and then, after the Berlin Wall, we had a string of movies about a meteor hitting the earth. And now, after 9/11, we've got terrorists and plague anxiety.

"Zombie movies tap into those apocalyptic fears and anxieties very effectively. They de-romanticize the connections between human beings and reduce humanity to its lowest common denomination, focusing on power relations in their most brutal human form. It's 'I will exert my will over you.' It's very Nietzsche-ian," Dendle says.

Romero, for one, doesn't like to wade into those deep waters to explain zombies' appeal.

"It's not about death or life after death or anything like that," the Pittsburgh native says. "If I had to boil it down, I'd say, it's the neighbors. That's the scariest thing in life, the neighbors — the strangers living next to us."

Romero may be the father of the modern zombie movie ("He invented the language," says producer Mark Canton), but he's never had an easy go of it, even when it comes to making his specialty. His four "Dead" films — "Night of the Living Dead" (1968), "Dawn of the Dead" (1978), "Day of the Dead" (1985) and now "Land" — have been made in different decades, not out of design, but because Romero has always insisted on doing things his way (the first three movies went out unrated), which has made him an outsider at studios.

"He's an author," says Asia Argento, daughter of Italian horror master Dario Argento, a collaborator of Romero's over the years.

"People think that because of my father I'm a horror screen queen, but I despise movies like 'Freddy vs. Jason' and 'Scream,' " adds Argento, who plays a prostitute/zombie fighter in "Land." "But with Romero, he has a personal style. His movies say something. If you're just interested in brains being splattered, you get that. But there's a message there, too."

And because the "Dead" movies have been spaced out (in more ways than one), it has given Romero what he calls a "terrific opportunity" to use each film to comment on the times.

" 'Night' grew out of the '60s, the beginning of the war, the violence of the streets," Romero says. "It was all about revolution, and I think in our minds, we were thinking about it being a failed revolution.

" 'Dawn' was just a comic book, man, bright and garish, 'Saturday Night Fever,' " he continues. "It's in your face, criticizing consumerism, the beginning of everybody going around thinking, 'If I have this stuff, I'm OK.' With 'Day,' it was just a darker period, and the film has these very unpleasant characters constantly at each other's throats."

In "Land of the Dead," class is the focus. Zombies have overrun the earth. Isolated pockets of humans remain in fortified enclaves. An elite few live the good life in a high-rise building, ignoring the dire realities — encroaching zombies, dissatisfied masses — by sipping champagne and maintaining appearances.

Read into it what you want, says Romero.

"I tried to give it a post-9/11 feeling, a society ignoring terrorism, poverty and other ills, living the corporate good life, pretending everything will be OK," Romero says.

"The beauty of Romero's movies is that there are so many different interpretations," says John Leguizamo, who plays a mercenary in "Land." "But the bottom line is zombies are just more frightening than any other monster. They're us. It could be your neighbor, your relative, your friend. It could be you. Or your ex-wife. It probably is your ex-wife."