LAKE FOREST, Calif. — Last week, it was the Rose Bowl players' breakfast. This month, it will be the World Economic Forum in Davos, Switzerland. Then the president's prayer breakfast in Washington, followed by an entertainment industry conference in Los Angeles.

Rick Warren, the Southern Baptist preacher's son from tiny Redwood Valley, Calif., is much in demand these days.

The founding pastor of the Saddleback mega-church south of Los Angeles and the author of the best-selling "The Purpose Driven Life," Warren is perhaps the most influential evangelical Christian in America.

With his book — the best-selling hardback nonfiction book in the nation — and Purpose-Driven Life videos and 40-day Bible study plans, Warren has created an unparalleled international network of millions of individuals and 400,000 churches, spanning faiths and denominations.

Now he wants to use his growing influence — and wealth — for an ambitious global attack on poverty, AIDS, illiteracy and disease.

"The New Testament says the church is the body of Christ, but for the last 100 years, the hands and feet have been amputated, and the church has just been a mouth. And mostly, it's been known for what it's against," Warren said during a break between services at his sprawling Orange County church campus.

"I'm so tired of Christians being known for what they're against."

Fresh from preaching to 38,000 congregants during Christmas week services, Warren was looking to the future by invoking the past.

"One of my goals is to take evangelicals back a century, to the 19th century," said Warren, 51. "That was a time of muscular Christianity that cared about every aspect of life."

Not just personal salvation, but social action. Abolishing slavery. Ending child labor. Winning the right for women to vote.

It's time for modern evangelicals to trade words for deeds and get similarly involved, Warren contends.

At the end of his second sermon last Sunday, he reminded his largely affluent Orange County audience: "Life is not about having more and getting more. It's about serving God and serving others."

That, simply put, is his message. Give your life to God, help others, spread the word. It is the same message that Christians have been preaching for 2,000 years. Warren has updated the language, added catch phrases and five-step guides, but he readily admits "there is not a new idea in that book."

"The Purpose Driven Life" has sold more than 24 million English-language copies since 2002, with millions more in other languages. It has been popular with Lutherans, Catholics, Baptists, Methodists and Presbyterians, with pastors and priests using it as a Bible-study handbook.

The book figured prominently in a hostage drama in Georgia last March. Ashley Smith, held by alleged Atlanta courthouse killer Brian Nichols, said he released her after she gave him methamphetamine and read to him from the book.

Warren "is able to cast the Christian story so people can hear it in fresh ways," said Donald E. Miller, director of the Center for Religion and Civic Culture at the University of Southern California. He is "a very important figure in evangelical Christianity," part of a "trend we'll see more of," Miller said, citing Warren's independence, social activism, informality and ability to reach across racial and national lines.

"The Gen X-ers are sick and tired of flash and hype and marketing," Miller said. "The soft sell of a Rick Warren is far more attractive to them than a highly stylized TV presentation of the Christian message."

Among evangelicals, Warren is more influential than better-known and more-divisive figures such as religious broadcasters Pat Robertson and Jerry Falwell or radio psychologist James Dobson, and is often seen as the heir to the Rev. Billy Graham as "America's pastor."

Scott L. Thumma, a professor of the sociology of religion at Hartford Seminary and the author of a forthcoming book on mega-churches, said polls of church leaders often put Warren in first or second place among most-influential evangelical leaders.

"And one of the interesting things is that he crosses boundaries. ... He's not just respected by the evangelical world but by many outside that world," Thumma said.

Broadly defined, evangelicals are Christians who have had a personal or "born-again" religious conversion, believe 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.

Millions of Americans fit the definition, although estimates vary on exactly how many. Forty-two percent of Americans described themselves as evangelical Christians in a Gallup poll in April, while 22 percent said they met all three measures in a Gallup survey in May. The National Association of Evangelicals says about 25 percent of adult Americans are evangelicals.

Evangelicals are often equated with fundamentalists or the religious right, which annoys Warren. Although he's politically conservative — opposing abortion and gay marriage and supporting the death penalty — he pushes a much broader agenda and disdains both politics and fundamentalism.

Warren is a friend of President Bush and a repeat visitor to the White House. But he also met for several hours at Saddleback last month with Sen. John Kerry, the 2004 Democratic presidential nominee, to discuss issues such as poverty and the environment.

"I'm worried that evangelicals be identified too much with one party or the other. When that happens, you lose your prophetic role of speaking truth to power," Warren said. "And you have to defend stupid things that leaders do."

As the money has rolled in from his book, Warren said, he has given most of the millions to the church and the three social-service foundations he has established.

He stopped taking his $110,000 annual salary and repaid the church for his 25 years of salary since its founding. He and his wife became "reverse tithers," he said, keeping 10 percent of their income and giving away the rest, including $13 million in 2004.