You do the math.

In his new novel, The Indian Clerk (Bloomsbury USA $24.95), about the relationship between two real-life figures-mathematician G.H. Hardy, a closeted say man, and Srinivasa Ramanujan, a possible mathematical genius--out author David Leavitt sets the intellectual world of Cambridge, England, against a backdrop of impending war.

Where did the idea for The Indian Clerk come from?

It began when I was writing about Alan Turing and researching the culture of Cambridge before World War I. I became intrigued by Hardy as a character and intrigued by his relationship with [Ramanujan].

Did you have to teach yourself certain mathematical concepts while researching the book?

I did have to teach myself, but it was fun. My education in mathematics was high school calculus, and I was always sort of taught that math wasn't something I was supposed to be interested in.

You've written both fiction and nonfiction. Do you have a preference?

Whenever I'm writing a novel, I envy nonfiction. You don't have to invent anything. It's a matter of finding out whet happened. When I'm writing nonfiction, I have the opposite complaint. But in my heart of hearts I'm a fiction writer, without question.

Was it easier, then, to write a novel about people who are dead?

Hardy was a slightly tricky case. The official line is that he was a nonpracticing homosexual, but I find that a little bit hard to believe. I very much wanted to make my Hardy at least distinctly gay.

Have you found being an out author has affected your career?

Initially, I think it profoundly affected me. It was really what defined me as a writer, but I think that was in some ways a reflection of the times. You don't see much anymore that tendency to label someone as a "gay writer." You can be openly gay and write about it without being identified as a gay writer, whereas in the past that identification was almost automatic.