When Martin Luther nailed his 95 theses upon the door of the Castle Church in Wittenberg, in 1517, he could hardly have imagined that he would succeed in spawning a new, Protestant branch of the Christian Church. He would also no doubt be surprised if he could see the direction Protestantism has taken in the past 500 years. What would Luther think if he were somehow to visit the state of Utah, essentially a homeland for the Mormon church—a movement born out of American Protestantism which is now one of the fastest growing movements in the country, with 5 million adherents in the U.S. alone and estimated assets of around 30 billion dollars? Or if he were to attend a service of the evangelist Toronto Blessing movement based in Canada, in which "a move of the Holy spirit" can lead to congregants barking like dogs, roaring like lions, and laughing uncontrollably?

The evolution of Protestantism is but a tiny example of the constant churning change taking place in the world of religion. And not only are established religions always mutating, but new ones are constantly being born. According to the World Christian Encyclopedia, an 800-page volume that attempts to track every religion practiced around the world, there are 9,900 distinct religions and two or three new religions created every day. A growing number of scholars are studying these new religious movements, or NRMs, concentrating on such questions as, What social conditions lead to the creation of new religions? How, exactly, do religions mutate? What was it about early Christianity or Islam or Buddhism that made those movements survive, when most new religions fail? In "Oh, Gods!" (February Atlantic), Toby Lester surveys these questions and others by looking at the study of NRMs.

One of the debates that continually roils the field of NRM scholarship is whether a distinction can really be made between cults and new religions—after all, many of today's established religious movements began on the fringes of society. Does this mean that the Hare Krishnas or the Wiccans could be the next big religion? It's unlikely, but stranger things have happened. One thing is clear, though—a hundred years from now, our religious landscape will look radically different than it does now. "What new religious movements will come to light in the twenty-first century?" Lester asks.

Who knows? Will that raving, disheveled lunatic you ignored on a street corner last week turn out to be an authentic prophet of the new world faith? All sorts of developments are possible. Catholicism might evolve into a distinctly Charismatic movement rooted primarily in China and headed by an African pope.... Membership of the Mormon Church might become predominantly Latin American or Asian. Scientology might become the informal state religion of California.... None of these possibilities is as unlikely as it may sound.

Lester, a senior editor at The Atlantic, has written two previous cover stories for the magazine, "The Reinvention of Privacy" (March 2001), and "What is the Koran?" (January 1999). We corresponded by e-mail earlier this week.

—Katie Bacon

How did you become interested in the subject of new religious movements?

Well, I've always been interested in religion as a social phenomenon, and one of the questions that I have often found myself returning to is why certain religious ideas and movements have caught on while others haven't. One has a tendency to think that today's major world religions—Islam, Judaism, Christianity, Buddhism, Hinduism—are just fixed elements of the religious firmament, but that's not the case at all, of course. Go back just a few thousand years, just a blip in human history, and none of those religions existed. And think of the fates of, say, Zeus, Odin, and Zoroaster, all gods who at one point or another in history lots of people felt were absolutely essential to the course of human events. If one can find this sort of flux in history, who's to say that other equally important and influential religions won't still emerge?

As I began to look into this a bit more closely, I found that there's as much religious flux now as there ever has been. The Mormons, for example, have only been around for a century and a half but already they're on the verge of becoming a world religion with millions of adherents and all sorts of cultural and political influence—even though in the nineteenth century they were regularly persecuted as an aberrant, blasphemous, and extremely dangerous cult. Ralph Waldo Emerson called Mormonism an "after-clap of Puritanism," the irony of which is hard to miss at a time when the Mormons are essentially hosting the Olympic Games and the Unitarians are only found in small pockets here and there around the country. Pentecostals at the turn of the twentieth century were laughed at as bizarre "holy rollers," but now it seems that in the coming century Pentecostals around the world may number as many as one billion. Falun Gong is another movement that has emerged almost imperceptibly, from the Western perspective, as a huge force in the world.

The closer you look at the religious landscape, the more of this sort of thing you find. So I decided to see whether there were people out there studying the dynamics of new religious movements. It turns out that this is actually a growing field, and I found myself intrigued by a lot of what these scholars had to say.

Have your own thoughts about religion shifted at all as you became immersed in the topic?

The main thing is simply that I've been surprised to discover just how much religious activity there is in the world. By this I don't just mean how many people describe themselves as religious, which is the usual indicator that people discuss, or how many people pray or go to churches or mosques or temples once a week. What I mean is the amount of mutation and schism that goes on in religious beliefs and practices. In my article I cite the claims made in the World Christian Encyclopedia—which is pretty much the best source out there on the makeup of the religious world—that every day some two or three new religions are formed, and that in the contemporary world some ten thousand religions are currently practiced. Those are astonishing figures. Thinking about religion in those terms has made me think of the evolution of religion in Darwinian terms—as a sort of "supernatural selection," you might say, in which mutation happens all the time, and in which diversity leads, a bit paradoxically, to the constant emergence of very hardy species that can adapt to evolving social situations. Most mutations fail, obviously, but every once in a while one comes along that is spectacularly well adapted to a new social environment and spiritual needs—and that's how a new religion takes off.

Can a realistic or meaningful distinction be made between cults and burgeoning religions?

Debates rage about this question, and I tried to avoid getting into it in my article, because it's such an emotional and inherently unresolvable issue, which makes debate about it very circular. The simplest way of answering it, though, is probably to say that a cult is a cult until it becomes successful. At that point it becomes a religion. People who study new religions observe that as religions become more successful, they gradually develop an orthodox structure and an internal hierarchy and a relatively low-tension relationship with society, all of which means that their initial cult-like feeling fades away. For example, to most Romans, Christianity seemed like just a weird cult of blood drinkers and cross worshipers—a "depraved, excessive superstition," as Pliny the Younger put it. What made Christianity succeed, in large measure, though, was its protean nature—it was able to find a place for itself in Roman culture, and then in other cultures, in the process transforming itself pretty dramatically. What would a second-century Christian think, say, of a Californian megachurch? Or a Latin American Pentecostal congregation? And vice versa? Which would be the cult?

The best expression I've found of the evolutionary dynamics I'm alluding to comes in William James's Varieties of Religious Experience. It's worth quoting at some length, I think.

A genuine first-hand religious experience," he writes, "is bound to be a heterodoxy to its witnesses, the prophet appearing as a mere lonely madman. If his doctrine prove contagious enough to spread to any others, it becomes a definite and labeled heresy. But if it then still prove contagious enough to triumph over persecution, it becomes itself an orthodoxy; and when a religion has become an orthodoxy, its day of inwardness is over: the spring is dry; the faithful live at second hand exclusively and stone the prophets in their turn. The new church, in spite of whatever human goodness it may foster, can be henceforth counted on as a staunch ally in every attempt to stifle the spontaneous religious spirit, and to stop all later bubblings of the fountain from which, in purer days, it drew its own supply of inspiration.

In writing this article did you get a personal sense of what it might be like to be a member of a new religious movement?

Yes and no. Initial converts to just about any religious movement, new or old, tend to feel pretty euphoric about the new community they've become a part of, and I imagine that that sort of feeling is remarkably similar from movement to movement. What's often particular to new movements, though, at least to successful ones, is a sense of being involved in a community that is ideologically and spiritually at odds with the surrounding society. Scholars of new movements generally seem to agree that for a new movement to succeed, it has to define itself against the status quo and be very demanding of its members. Movements that just allow people to come and go, without a lot of commitment and sacrifice, tend to fail pretty quickly. So I'd say that in a lot of new movements there's probably a bit of a siege mentality, which, of course, is exactly the sort of bonding experience that people often are in search of when they choose their religion.

Why do you think some new religions are successful and others aren't?

That's a complicated question, involving all sorts of factors, including the charisma of the founder, the social environment and the political system into which the religion is introduced, and a lot of pure chance. The one scholar I came across who has actually dared to put into print what he feels are the reasons a religion succeeds is the sociologist Rodney Stark, who in 1996 wrote an article in the Journal of Contemporary Religion called "Why Religious Movements Succeed or Fail." He listed ten factors that he felt are essential to a religion's success, some of which I can try quickly to summarize for you here. 1) Cultural continuity with the society at large. Mormonism has succeeded, for example, because of how much it emphasizes the heritage it shares with Christianity. 2) They exist at a moderate level of tension with society—they're "strict, but not too strict," Stark says. 3) They can create a highly motivated group of volunteers who gladly will work for the community and many of whom will actively proselytize. 4) They have enough children to keep membership strong, and they work at keeping their children engaged in the religion. 5) They seek out an open "market niche," as it were, and exploit it well. 6) They exist in a political climate that is at least somewhat tolerant of religious unorthodoxy. Stark goes on at much greater length, and in much greater detail, but those are some of the things he thinks are pretty important. Obviously a charismatic leader is crucial at the outset, too, but charisma alone won't do it—to succeed a movement quickly has to give itself a structure and an identity that is both strong and adaptable.

You write that "in the period after World War II so many new religious movements came into being in Japan that local scholars of religion were forced to distinguish between shin-shukyo ('new religions') and shin-shin-shukyo ('new new religions')." Is there any sort of link between violent societal upheaval caused by war or poverty and the sprouting of numerous new religions?

I would imagine so, particularly in that violent social upheaval usually happens very fast, whereas established religion—think of the Catholic Church—moves very slowly and often can't keep up. It's often said that new religious movements do well because they are so small and can therefore adapt to changing social environments very quickly. As that new social environment settles down and becomes established, so do the religious movements that grew up along side it. Speaking of poverty and social upheaval, incidentally, it's interesting to note that India's "untouchables," now known as Dalits, have regularly flirted in recent years with the idea of a mass conversion out of Hinduism and into another religion, notably Christianity. If tensions became severe between the Dalits and Indian culture at large, it's not inconceivable that such a conversion could take place, which would suddenly make Christianity a sort of new religious movement among millions of people. Context is everything.

You point out that members of NRMs tend to be young, well educated, and relatively affluent. This certainly doesn't fit with most people's ideas of who might join the Hare Krishnas, the Moonies, and so on. In general, what is it that draws people to these new religions?

It's hard to generalize, because there are so many different kinds of movements, and so many different social situations in which new movements emerge, but it does seem that the initial membership of new movements is often dominated by the young, the well educated, and the affluent. I suppose this probably has something to do with the facts that the young like new things that get their parents upset; that more education generally leads to an openness to new ideas; and that affluence often leads to a sort of selfishness and materialism that can suddenly seem appallingly corrupt to those who have grown up in it. But in the end I'd say that what really draws people in to new movements is that they offer, as one scholar put it to me, a "high octane" brand of religion. It's kind of a thrill, just as attending an African-American gospel service might be for a Catholic. There's a vitality and passion there that just makes an emotional connection. Rodney Stark tries to disabuse his readers of the idea that somehow there's something that you meaningfully might call "theological refinement" in religion; his point is that if a religion becomes an intellectual pursuit, full of abstract and metaphorical notions about spirituality, and loses touch with the passion and zeal and self-sacrifice that created the original movement, it's lost. The same thing goes for music, come to think of it—new, less-refined versions of it are born all the time, and these versions have a cult-like appeal, especially to the young, the affluent, and the well educated. The same standard of success applies, too: the Beatles were a deviant cult until they became successful, which meant soon enough that the Queen knighted them and new musical movements emerged that emulated them—or even rejected them.

Do people in the U.S. tend to be drawn to NRMs for different reasons than people in, say, Africa?

On the surface, maybe, but I'd say that at root what draws people to new religious movements is what I've just described—that high-octane sense of passion and community. And what keeps them there is pretty much the same everywhere, too, I think—the simple and obvious fact that they work, in terms of how they allow individuals to function in society. The African example is a good one. I was told repeatedly as I reported my article that new religious movements, particularly Christian ones, are extraordinarily popular in Africa, and that this is in large part due to the fact that these movements are now trans-national. A lot of Africans have to be very mobile in search of work, and these new trans-national movements allow them to feel at home and part of a larger community whether they're in Ghana or Botswana.

You describe the sociologist Rodney Stark's rational-choice theory of religion as one of the primary ways that people are theorizing about religion today. According to this theory, you write, "in a free-market religious economy there is a healthy abundance of choice (religious pluralism), which leads naturally to vigorous competition and efficient supply (new and old religious movements). The more competition there is, the higher the level of consumption." This would seem to mean that we should get fewer new religions—and perhaps slower evolution of established religions—in countries with repressive regimes. Does this seem to be the case?

Well, I would suspect that no matter where you are you'll find people coming up with new religious movements, but I do think it's fair to say that these new movements can't succeed very well if they're politically persecuted in their early stages. One theory has it that Christianity survived and thrived in the Roman empire because initially it was considered just too marginal to pay much attention to. There was the occasional Christian thrown to the lions or something, but in the larger picture—which at the time involved all sorts of cults and movements from all over the Roman empire—Christianity just didn't seem like much of a political threat. Rodney Stark cites the strength of a religious "free market" in order to explain the odd paradox that the United States is a pretty fervently religious country even though its constitution explicitly sets up a wall between religion and politics.

What do you see as the future for a big religion like Islam, which in some ways seems resistant to change and slow to evolve?

I think the idea of Islam as an unchanging monolith is a very misleading one. Islam is full of variety and schism and factionalism—which is another way of saying it's still full of life, notwithstanding the contemporary focus on the static and uncompromising vision of bin Laden and his crew. It's hard to imagine that Islam won't play a major role in the world for centuries to come. What's interesting, actually, is to think of groups like the Muslim Brotherhood and the Taliban and al Qaeda as new religious movements themselves—each one emerged in the twentieth century, after all. If they conform to what scholars have learned about the emergence and evolution of new movements, either they'll wither away or they'll become more and more mainstream, which will mean that they'll evolve ways of more peacefully coexisting with society. And if they enjoy a measure of success in the meantime, perhaps that will lead to a pendulum swing toward new movements in Islam. I've recently seen reports, for example, that Sufism is undergoing a bit of a revival. And I was interested to learn in researching my piece that there's also a major new schismatic Islamic movement known as the Ahmadi movement, which is only a little more than a century old, that was created by a "successor" prophet to Muhammad. It's based in Pakistan, claims to have millions of members, and seems to have global reach. Right now the groups suffers considerable persecution and is banned from making the pilgrimage to Mecca, but one could make the case that the Ahmadis are a bit like Islamic Mormons, practicing a divergent yet culturally continuous brand of religion—and that precisely because of that, and despite the "heresy" of their new beliefs, they have a reasonable chance of success, at least in the religious free market.