Almost anywhere you look around the world, with the glaring exception of Western Europe, religion is now a rising force. Former Communist countries are humming with mosque builders, Christian missionaries and freelance spiritual entrepreneurs of every possible persuasion. In China, underground "house churches" are proliferating so quickly that neither the authorities nor Christian leaders can keep reliable count. In much of South and Central America, exuberant Pentecostal churches, where worshippers catch the Holy Spirit and speak in tongues, continue to spread, challenging the Roman Catholic tradition. And in the United States, religious conservatives, triumphant over their role in the re-election of President Bush, are increasingly asserting their power in politics, the media and culture.
The tsunami in Asia could spur religious revival as well, as victims and onlookers turn to mosques, temples and churches both to help them fathom the catastrophe and to provide humanitarian assistance.
What does all this rising religiosity add up to? It is easy to assume that a more religious world means a more fractious world, where violent conflict is fueled by violent fundamentalist movements.
But some religion experts say that while it is clear that religiosity is on the rise, it is not at all clear that fundamentalism is. Indeed, there may be a rising backlash against violent fundamentalism of any faith.
The world's fastest growing religion is not any type of fundamentalism but the Pentecostal wing of Christianity. While Christian fundamentalists are focused on doctrine and the inerrancy of Scripture, what is most important for Pentecostals is what they call "spirit-filled" worship, including speaking in tongues and miracle healing.
Most scholars of Christianity believe that the world's largest church is a Pentecostal one — the Yoido Full Gospel Church in Seoul, South Korea, which was founded in 1958 by a converted Buddhist who held a prayer meeting in a tent he set up in a slum. More than 250,000 people typically show up for worship.
"If I were to buy stock in global Christianity, I would buy it in Pentecostalism," said Martin E. Marty, professor emeritus of the history of Christianity at the University of Chicago Divinity School and a co-author of a study of fundamentalist movements. "I would not buy it in fundamentalism."
After the American presidential election in November, some liberal commentators warned that the nation was on the verge of a takeover by Christian "fundamentalists."
But in the United States today, most of the Protestants who make up what some call the Christian right are not fundamentalists, who are prone to create separatist enclaves, but evangelicals, who engage the culture.
For example, at the fundamentalist Bob Jones University, in Greenville, S.C., students are not allowed to listen to contemporary music of any kind, even Christian rock or rap. But at Wheaton College in Illinois, a leading evangelical school, contemporary Christian music is regular fare for many students.
The word "fundamentalist" itself has fallen out of favor among conservative Christians in the United States, not least because it has come to be associated with extremism and violence overseas.
Fundamentalism in non- Christian faiths became a phenomenon in the rest of the world in the 1970s, said Philip Jenkins, a professor of history and religious studies at Pennsylvania State University.
"From the 1970s on, you get the growth of not just more conservative religion, but religion with a political bent," said Jenkins, the author of "The Next Christendom: The Coming of Global Christianity."
Now, the future of fundamentalism is murky, with several contradictory trends at work simultaneously.
There is little doubt that one fundamentalism can feed another, spurring recruitment and escalating into a sort of religious arms race. In Nigeria's central Plateau State, Muslim and Christian gangs have razed one another's villages in the last few years, leaving tens of thousands of dead and displaced. In rioting in India in 2002, more than 1,000 people, most of them Muslims, were killed by Hindus in Gujarat state — retaliation for a Muslim attack a day earlier on a train full of Hindus, which killed 59.
Husain Haqqani, a Pakistani political commentator and visiting scholar at the Carnegie Endowment for International Peace in Washington, said that insurgents in Fallujah, Iraq, recruited fighters with the false rumor that Christian crusaders with the Rev. Franklin Graham's aid organization, Samaritan's Purse, were on the way over to convert Muslims. (Graham is known throughout the Muslim world for his statement that Islam is a "very evil and wicked religion.")
Fundamentalism does not necessarily lead to intolerance, Jenkins said. "People with very convinced, traditional views can get along together for a very long time," he said. "But sometimes we get into cycles where they can't, and we seem to be in one of those cycles right now."
Analysts are also seeing signs of a backlash as religious believers grow disenchanted with movements that have produced little but bloodshed, economic stagnation and social repression.
In last year's elections in India, voters repudiated the ruling Bharatiya Janata Party, a Hindu nationalist group whose cadres had helped stir up violence in some Indian states against Muslims and others.
And in Indonesia, mainstream Islamic groups in September helped elect as president a secular general who had been relatively outspoken about the threat posed by the radical group Jemaah Islamiyah, which is responsible for several acts of terrorism.