In Holy Ghost Girl, Donna Johnson grows up under the influence of an evangelical preacher.

Tent preaching was dying out when you were on the circuit with Brother David Terrell as a child. What made him so successful?

He had this perseverance that drove him, much like what drives successful businessmen . He also had amazingly powerful charisma, combined with good looks and a sort of humbleness and a real ability to connect, at least onstage. It inspired love in people. Finally—and this is the part that's hardest for people to understand—all of those tent preachers really believed. Most of them come from what we call "holiness" backgrounds, the backwoods churches. David Terrell really believed that he had this special calling to do this great work. And he was enough of a performer that he was able to communicate that on a cellular level to people. He's exciting to watch.

Did you always know that you wanted to write about your time on the tent circuit?

I think I did. In college, I knew that my most powerful essays came from writing about my childhood. I received a lot of encouragement from my professors. But I realized that in my 20s I wasn't ready for the very difficult personal undertaking of writing that story. I think it seemed too sad to me then, and I didn't have a handle on how funny it was or how to disengage from it enough to see it purely as a story. To tell that story, I had to overcome tremendous psychological resistance. It's surprising what we carry from our childhood, especially this idea that we should keep things secret. I know that sounds very Oprahesque.

How does power—from star power to the abuse of power—factor into Terrell's life and your life?

People were always very reluctant to question him. When I was younger, I remember people having arguments about scripture and theology. But as he consolidated power, there were more and more people around him saying "yes" to everything he thought and everything he wanted. I think he was able to justify whatever he did with an evolving theology and a very literal interpretation of scripture. To me, that's very scary. I didn't say this in the book, but when I saw the Guyana tragedy [with Jim Jones] on TV, I thought, thank goodness David Terrell never said drink the Kool-Aid, because I think a lot of them would have.

Is he still preaching now?

He is. He might put up a tent that holds about 2,500 and there might be 100 people, 200 people at the most. It's a sad thing to see. He was a father figure to me so I still have these feelings tied up the way anyone would who has a dad who's cruel or an alcoholic, but still has feelings for him. I've gone to the tent revivals, and he's just a remnant of what he once was. He does it because that's his idea of who he is.