In Conclave, Harris takes readers behind the scenes at the Vatican for the selection of a new pope.

Where did the idea for Conclave come from?

When I watched Pope Benedict step out onto the balcony of St. Peter’s after his election as pope in 2005, and again when Pope Francis appeared in 2013, I wondered each time what process had occurred behind the scenes to elevate them to this supreme office. That planted the seed, and as soon as I had some free time, I began to research how conclaves operate. Immediately I saw it was a wonderful subject for a novel.

How did you get such detailed information about the process?

I read everything I could lay my hands on. The best single source was a so-called secret diary kept by a cardinal who was present during the 2005 conclave. It was published in a South American magazine and is clearly genuine and accurate. I wrote to the Vatican and asked if I could have access to the places where a conclave happens—in particular, the guest house within the walls of the Holy See called the Casa Santa Marta, where the cardinals live during the election and where all the politics takes place between the ballots. They kindly said yes. I also spent time in the pope’s private chapel, the Pauline, and saw the Room of Tears, the sacristy off the Sistine Chapel where the new pope is robed. That access was hugely important.

Is the political horse trading you describe in the book inevitable?

Yes. A candidate needs two-thirds of the votes to be elected. The cardinals are locked into the Sistine Chapel and are required to hold four secret ballots per day until a winner emerges. It is between the ballots, in the lunch breaks and in the evenings, that the politics happens. The cardinals gather in one another’s rooms, in the corridors and in the dining rooms. There are factions. They switch their votes, trying to rally the maximum support behind the candidate who best represents their view. It’s nothing new. This has been going on for seven centuries.

Does this novel share any themes with your other works of fiction?

Yes, very much so. A conclave is, in essence, albeit cloaked in sacred ritual, a struggle for power, and all my books are about power, in one form or another. Often they are centered on small groups in which there is a struggle for control. I also like to write novels with a very tight time frame and location. In a sense, Conclave is my apotheosis: the most absolute, the oldest, the most concentrated electoral process in the world.