Television evangelists often tell stories of those in despair who found their faith.

For Dan Barker, the process was reversed. A former minister and evangelist, Barker is now a devout atheist.

For 17 years, Barker toured the country as a musical evangelist. He produced and arranged a number of Christian recordings and wrote several popular children’s Christmas musicals.

With such a track record, this ordained minister was not the type of person one might expect to one day become co-president of the Freedom From Religion Foundation, an atheist organization that argues there should be an absolute separation between church and state.

The organization has filed and won many lawsuits against government and religious institutions they believe have violated this separation.

Barker announced his atheism publicly in 1984. He is scheduled to speak at 7 p.m. Thursday in the Great Hall of the Memorial Union as part of First Amendment Days in celebration of the freedom of religion. He said his speech will detail how he arrived at his decision to become an atheist.

“It was a gradual process, a growth,” Barker said. “It would be like asking you, ‘When did you grow up?’ You probably could not answer that question with one ‘defining moment,’ but you could probably point to a period in your life when you finally realized that you had grown up.”

Barker joined the Freedom From Religion Foundation in 1987 as its public relations director. He is a contributing editor of its newsletter, Freethought Today, and has published many books through the organization, including “Losing Faith in Faith.”

The ISU Atheist and Agnostic Society planned the event.

Cole Baessler, freshman in pre-architecture, arranged for Barker to speak on campus.

“I had recently read Barker’s book, ‘Losing Faith in Faith,’ and thought Barker was an excellent advocate for atheism,” Baessler said. “His views are insightful and eloquently expressed. He has led an interesting life, and I hoped his turnaround from minister to atheist would interest both the religious and non-religious.”

Barker says antagonism from Christians is rare at his speeches, although they are there and they often ask him difficult questions.

“Most college students expect a university to allow diverse points of view,” Barker says. “After all, the Christians expect us atheists and agnostics to attend their events and to listen carefully to what they say. Most people have an innate sense of fairness about these things.”

Laura Bergren, senior in English and a leader of the campus Christian group The Salt Company, said a few of the group’s members are planning on attending.

“I’m sure there will be at least a few … There are quite a few qualified individuals in the area who can provide the answers to the questions he brings up,” Bergren said.