PROVIDENCE, R.I. — Kevin Roose managed to blend in during his single semester at Liberty University, attending lectures on the myth of evolution and the sin of homosexuality and joining fellow students on a mission trip to evangelize partiers on spring break.

Roose had transferred to the Virginia campus from Brown University in Providence, a famously liberal Ivy League school. His Liberty classmates knew about the switch, but he kept something more important hidden: He planned to write a book about his experience at the school founded by fundamentalist preacher Jerry Falwell.

Each conversation about salvation or hand-wringing debate about premarital sex was unwitting fodder for Roose's recently published book: "The Unlikely Disciple: A Sinner's Semester at America's Holiest University."

"As a responsible American citizen, I couldn't just ignore the fact that there are a lot of Christian college students out there," said Roose, 21, now a Brown senior. "If I wanted my education to be well-rounded, I had to branch out and include these people that I just really had no exposure to."

Formed in 1971, Liberty now enrolls more than 11,000 residential students, along with thousands more in Liberty's distance-learning programs. The university teaches creationism and that the Bible is the inerrant word of God, while pledging "a strong commitment to political conservatism" on campus and a "total rejection of socialism."

Roose transferred to Liberty for the spring 2007 semester. He was determined to not mock the school, thinking it would be too easy — and unfair. He aimed to immerse himself in the culture, examine what conservative Christians believe and see if he could find some common ground.

He had less weighty questions too: How did they spend Friday nights? Did they use Facebook? Did they go on dates? Did they watch "Gossip Girl"?

It wasn't an easy transition. Premarital sex is an obvious no-no. So are smoking and drinking. Cursing is banned, so he prepared by reading the Christian self-help book, "30 Days to Taming Your Tongue."

He lined up a publisher — Grand Central Publishing — and arrived at the Lynchburg campus prepared for "hostile ideologues who spent all their time plotting abortion clinic protests and sewing Hillary Clinton voodoo dolls."

Instead, he found that "not only are they not that, but they're rigorously normal." He met students who use Bible class to score dates, apply to top law schools and fret about their futures, and who enjoy gossip, hip-hop and R-rated movies — albeit in a locked dorm room.

A roommate he depicts as aggressively anti-gay — all names are changed in the book — is an outcast, not a role model. Yet some students also grilled him about his relationship with Jesus and condemned non-believers to hell.

Roose researched the school by joining as many activities as possible. He never blew his cover, even ending a blossoming romantic relationship rather than come clean. He revealed the truth on a return trip to campus.

He grappled with guilt during the entire project, but said he ultimately found forgiveness from students for his deception.

The university administration has been less receptive. Chancellor Jerry Falwell Jr. said in a statement that Roose had a "distorted view" of Liberty before he arrived and gave an incomplete portrait of the school.

Once ambivalent about faith, Roose now prays to God regularly. He owns several Bibles and has been rereading meditations from the letters of John — and he's even considering joining a church.