Kushner’s new novel, The Mars Room (Scribner, May) follows former sex worker, single mother, and convicted killer Romy Hall as she begins serving two consecutive life sentences in a California women’s prison.

How did you come to be interested in prison as a subject?

It’s always unsettled me that we have this system where people have to be taken away from their families and go to prison, and I think it’s worth asking some very fundamental questions without judgments or polemical self-righteousness. Take the prison-building boom in California—it’s not a simple story. It has to do with the economy, the drought, and land surplus. At a certain point, I felt that the work of writing fiction is to try to reproduce these things that are not easily reducible.

Was it difficult to write imprisoned characters whose fates are, in a sense, foreknown?

The bigger challenge was how to give them full humanity, vitality, and comic moments. I think the book had to be funny for it to work for me, somehow. It can’t just be about the grimness of what middle-class people imagine prison to be like. Those who are sent to prison are living in a very small world. They’re stuck in one place and cannot leave it, but then that world blooms with complexity.

One of my favorite characters was Conan, who reads as transgender. Were you trying to bring awareness to the situation of trans prisoners?

Conan came to me so naturally. That said, women’s prison is a place where genders seem to quite naturally span out across the spectrum. They take on the roles of a truly mixed population and that’s probably been going on forever. There are men, boyish women, tough but feminine women, ultragirly women; people just get to have roles in prison that they should probably also have in the real world. But the absence of men, I think, allows a certain version of men to flourish.

Was it difficult making criminals sympathetic?

Honestly, I didn’t think of the audience once when I was writing this book. I don’t know if I could do it otherwise; I wrote it in such a private space. It’s not about an abstract reader or me as any kind of public person. I find both those things slightly suffocating; even if it’s lucky to be in a position where I would have readers, I don’t care about being read. Sadly for my publisher.

As for Romy, it’s a logical question because the elephant in the room is “What am I to think of somebody who has committed a horrific act of violence?” I think it would be bad fiction to make it perfectly defensible, to be the sort of guilty character that can be perceived as innocent for the reader. No, she is guilty. I wanted the book to have some relationship to reality.