In 1960, there were an estimated 50 million evangelical Christians in the West, and 25 million in the rest of the world; today, there are an estimated 75 million in the West, and 325 million in the rest of the world (representing about 20 percent of the two billion Christians worldwide), according to Robert Kilgore, chairman of the board of the missionary organization Christar.

Other experts differ on the number of evangelicals (estimates range from 250 million to nearly one billion) but agree that the number is growing rapidly.

"As the vibrancy of evangelicalism seems to have waned somewhat in the West, many in the non-West are ready to pick up the banner and move forward," said Kilgore, a former missionary who is now associate provost at Philadelphia Biblical University. "Most Americans have no idea how big the shift has been."

Todd M. Johnson, director of the Center for the Study of Global Christianity, writes that "Africans, Asians and Latin Americans are more typical representatives of evangelicalism than Americans or Europeans."

The new evangelicals are more exuberant in their worship services; put more faith in spiritual healing, prophecy and visions; and read the Bible more literally than many of their Western cousins.

And many of the new evangelicals are on the fault lines of global unrest, where cultures and religions collide. Christianity and Islam are often competitors in these developing countries, and some scholars, such as Philip Jenkins of Pennsylvania State University, see the possibility there for cataclysmic conflict.

"A worst-case scenario would include a wave of religious conflicts reminiscent of the Middle Ages, a new age of Christian crusades and Muslim jihads," Jenkins writes in his book, The Next Christendom: The Coming of Global Christianity. "Imagine the world of the 13th century armed with nuclear warheads and anthrax."

Others think such dire scenarios are far-fetched but see decades of friction ahead as Christianity and Islam compete, especially in Africa and Asia.

Evangelicals are among the fastest-growing segments of Christianity. Their global numbers are increasing at about 4.7 percent a year, according to Operation World, a Christian statistical compendium.

By comparison, the rate of growth for all Protestants is put at 2.2 percent a year, and for Roman Catholics at 0.5 percent a year. The world's population is growing at about 1.4 percent a year.

Broadly defined, evangelicals are Christians who have had a personal or "born-again" religious conversion, believe that the Bible is the word of God, and believe in spreading their faith. (The term comes from Greek; to "evangelize" means to preach the gospel.) The term is typically applied to Protestants.

American evangelicals have gotten most of the public attention because they're in the center of the media universe and because they played a pivotal political role in the 2004 U.S. election. But American evangelicals are a distinct minority, and their beliefs and practices are often significantly different from those of evangelicals elsewhere.

In Africa, some evangelicals practice polygamy. In China, some revere their ancestors. In South Korea, many believe in faith healing and the exorcism of evil spirits.

The melding of local traditions with Christianity has produced a religion that looks unfamiliar to many Westerners but is "vast, varied, dynamic and lively," said Joel Carpenter, provost and professor of history at Calvin College, an evangelical college in Grand Rapids, Mich. Carpenter, an editor of The Changing Face of Christianity, is soon to be director of the new Nagel Institute for the Study of World Christianity at Calvin.

Evangelicals in the global South and East are, in many ways, at least as conservative as their U.S. counterparts. But they often diverge on such issues as poverty and war.

"On abortion or gay marriage, they sound like American conservatives. But on war and peace or economic justice, they sound like the Democratic Party," Carpenter said. "And I have not met one foreign evangelical leader that approves of American foreign policy."

Non-Western evangelicals may already be charting new directions with new leaders that the old bastions of Christianity are unaware of, said Mark Noll, a professor of history at Wheaton College.

"Historically, in unpredictable places and unpredictable times, you get real savvy leaders," Noll said. "I suspect that in Beijing, Nairobi or Cape Town, things will be very well along with innovation before Philadelphia, Chicago or London is aware of it.

"Almost everything that's significant takes place below the radar screen," he said.

John H. Orme, executive director of the Interdenominational Foreign Mission Association, an alliance of evangelical mission groups, said the old citadels of Christianity could learn from the new.

"I wish the Third World would have more effect on us," he said. "The church in the developing world is much more alive to the working of the holy spirit."

Kilgore said "many Westerners feared they [foreign evangelicals] would mess it up, but the more they've taken their own course, the more it has produced growth. If there is anything that encourages me, it is that Christianity is no longer a U.S. or Canadian or European-dominated religious system."

"We help where we can, but we have to stay away from being Uncle Sam and telling them how to do it."

As the new evangelicals expand their influence and their territory, they face confrontation with other religions, most often Islam. The issue of how the world's two biggest religions will interact "is a fantastically important question," said Lamin Sanneh, the D. Willis James professor of Missions and World Christianity at Yale Divinity School.

Muslims represent about 20 percent of the world's population, compared with Christians' 33 percent. But Islam is growing more rapidly than Christianity, largely because of faster population growth in Muslim countries, and it may surpass Christianity as the world's most popular religion in this century.

Sudan, Nigeria and the Balkans offer recent examples of violence between Christians and Muslims. But there are other examples, such as South Africa, where the two religions coexist peacefully, said Sanneh, a native of Gambia who is the author of Whose Religion Is Christianity? The Gospel Beyond the West.

In Islamic countries, the Western notion of separation of church and state is largely unknown, and Sanneh said American Christians ought to better explain the advantages - to both religion and government - of keeping the two separate.

"The American experience on that is relevant to the rest of the world in a remarkable way," Sanneh said. "Americans confronted that centuries before the rest of the world."

After centuries of receiving missionaries from colonial powers in the West, evangelicals in Africa and Latin America and Asia are now planting churches in the United States and Europe. As immigrants arrive here, many bring their own brand of evangelical Christianity with them, while others start churches specifically to minister to "post-Christian" Westerners.

The shift of the global center is unsettling to many American evangelicals used to the old order.

"It will be humbling for the North," Carpenter saod.

But he and Noll, the Christian historian at Wheaton, said this latest transformation of evangelical Christianity should be seen less as a loss of the old than a triumph of the new.

"When I'm thinking like a historian, I tend to be a little depressed," Noll said. "But when I'm thinking like a Christian, I tend to be optimistic."

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