You've heard about how you're not supposed to talk about religion in polite company?

Then here's something that really has the potential to create fireworks: talking about the opposite of religion in polite company.

Discourteous or not, the flip side of religious belief -- call it atheism, agnosticism, humanism, rationalism, secularism, freethinking, nontheism or just basic nonbelief -- is everywhere these days, from best-seller lists to TV news shows to workplaces, churches, barrooms and anywhere else humans tend to hash out life's cosmic questions.

Color Mel Lipman surprised. Just two years ago, the Las Vegas attorney and president of the American Humanist Association felt he was swimming against the current in lobbying for Americans to accept other Americans who don't believe in a supreme being.

"Now, I feel that the current has kind of stopped running against me," Lipman said. "I'm still not being pushed by it, but at least I'm treading water, and that's better than what I was doing before."

Which means nontheism remains some distance from mainstream thought. Lipman maintains that religious nonbelievers even now continue to be "the most discriminated against group" in America.

Still, he and others in the nontheist/atheist/humanist movement are encouraged that nonbelief is enjoying a higher, and generally more positive, public profile now than it has had in decades.

"I think there is a new awareness

it is a legitimate form of belief," Lipman said. "Before, there just wasn't that kind of awareness. It's just treating the other (nontheistic) side with respect where, in the past that kind of respect wasn't due the other side."

"My sense is that the mainstream educated American is more open to nonbelief than ever before," agreed James Underdown, executive director of the Center for Inquiry-West, a California-based nonprofit organization whose mission includes promoting reason and providing "rational ethical alternatives" to religious belief systems.

"I think people are more openly interested in these subjects and are at least more inquisitive about it," Underdown said.

"I think, generally, we're having an easier time," said Lori Lipman Brown who, as director of the Secular Coalition for America, lobbies in Washington, D.C., on behalf of atheists, humanists and other nontheists. "People at least are acknowledging we deserve to have a place in society and can live beside us peacefully and with some degree of respect."

It's hard to pin down exactly how many Americans identify themselves as atheists, humanists or nontheists. Lipman has seen figures that nontheists make up anywhere from 11 percent to 15 percent of the U.S. population, which would equate to as many as 45 million Americans who don't believe in God, gods or other sorts of higher powers.

What Lipman does know is that membership in his organization -- one of many that revolves around religious nonbelief -- has increased 250 percent, to about 8,000, during the past four years alone.

That's "remarkable," he added, "because it's been steady for maybe the previous 20 years."

Underdown traces the beginnings of nontheism's current public renaissance to the early '80s and the rise of the Moral Majority when, he said, "an organized group of Christians began to foist their belief system on the rest of Americans."

The Sept. 11, 2001, attacks at the World Trade Center and the Pentagon by Islamic extremists also helped to stoke a nagging suspicion among many Americans that, Underdown said, "religion is contributing to a lot of the death and destruction in the world."

A turn toward nontheism may be linked to some Americans' perception that the Bush administration hews too tightly to a far-right Christian philosophy and is weakening the traditional wall between church and state.

"Every time the country goes to one extreme, there's a tendency to go back to the other side," Lipman said. "And with the Bush administration, we have a very, very right-wing fundamentalist mind-set where, more and more, religion is being pushed into government, which makes nontheists feel more and more uncomfortable, and we feel we've got to defend ourselves against this creeping theocracy."

Also helping to bring atheism into the public eye have been several best-selling books -- including Christopher Hitchens' "God is Not Great: How Religion Poisons Everything"; Sam Harris' "The End of Faith: Religion, Terror and the Future of Reason"; and Richard Dawkins' "The God Delusion" -- which lay out the case for nonbelief and landed their authors high-profile appearances on everything from news shows to even, in Hitchens' case, Comedy Central's' "The Daily Show."

"This is the first time in recent history, because of Dawkins and Harris and some of the other writers, that this information (about atheism) is becoming public," Underdown said. "And I think more and more people are saying, 'Wow, maybe (religious belief) isn't resting on a foundation as solid as I once believed.' "

Finally, add to all of this the Internet's ability to connect questioning believers or nonbelievers to both information about nontheistic philosophies and like-minded people and organizations. The result: Atheism's appearance on America's cultural radar to a degree not seen since the late Madalyn Murray O'Hair convinced the U.S. Supreme Court in 1963 to bar state-run prayer from public schools.

Brown -- Mel Lipman's daughter and herself a former Nevada state senator -- noted that from her first days as a lobbyist two years ago, "I was getting phone calls from all over the country, but especially from the Bible Belt area and parts of the South, from people saying, 'I've been so scared to tell anyone that I don't believe in a god, and I'm so glad you're there.' They'd be on the phone almost crying."

Brian Govatos, now 20, realized he was a nontheist at 17. Raised in the Church of Jesus Christ of Latter-day Saints, Govatos describes himself as an "antitheist," somebody who "actively opposes organized religion and focuses primarily on the destructive and negative aspects of it, while acknowledging the positive as well."

He called his path to nontheism a "slowly developing enlightenment" that began when he started to see churches -- his own and others -- "as a business entity, and really began to understand the inner workings and the politics."

His family remains in the LDS church, and Govatos said his lack of religious belief is "a primary topic when I go to my parents' house for dinner or things like that."

But he, too, has sensed that the American public is more willing to talk about, and consider, nontheistic philosophies than it did even three years ago.

"It's almost as if Dawkins, Harris and Hitchens added a level of credibility to the position of atheism," he said. "When my parents see a (story) on Fox News about atheists, they go, 'Oh, atheism.' It's open to discussion now. Before, it was just taboo because it was just their crazy, kooky son talking at the dinner table."

Las Vegan Carl Kaun agreed that the Hitchens and Dawkins books "give you an opening that you didn't have" before to discuss nontheism. "It gives some gravitas, as it were, to bring the topic up and say, 'Here's what people are saying about religions.' "

Kaun, 60, who's retired from a career in the aerospace industry, two years ago moved from the San Diego area to Las Vegas. He describes himself as "an apatheist," or someone who "doesn't really concern himself" with whether there is a god.

Kaun said nontheism "kind of crept up on me" over the past decade or so. Through online chats about atheism, "I just became more and more comfortable, I guess, with the idea that I didn't believe in any deity, and it actually seemed to be more and more foolish," he said.

Kaun has no qualms about talking about his beliefs. Yet, he said, some nontheists he knows "are concerned about other people knowing they are atheists because they still fear being discriminated against."

For example, Kaun knows of a teacher who's open about her beliefs with other nontheists but doesn't talk about them to others.

Lipman said that, based on missives to his group, blatant discrimination toward nontheists has become rare, although there are reports of "very subtle forms of pressure."

For example, he still hears from parents whose kids are "being pushed around on the schoolyard, harassed or ostracized because they don't say, 'under God' in the pledge (of allegiance)."

On the other hand, Lipman also receives e-mails from believing students who wish to learn about humanism for their religion studies classes and adults who simply wish to learn more about it.

"These are people who are not even questioning their own faith but want to learn about other views where, previously, they didn't even know these views even existed," he said.

Also new: Lipman has received, and accepted, invitations to speak to church groups during the past few years.

Most, he said, "just want to hear about what justifies my beliefs, and the questions are challenging, but not done with any kind of antagonism."