Proctor, a man responsible for ferrying old souls into new bodies, discovers that his utopian world is not what it seems in bestseller Cronin’s The Ferryman (Ballantine, May).

Where did the idea for The Ferryman come from?
My philosophy is that you have to write the book that’s asking you to write it. I was up in Cape Cod on a beautiful starry night, and three things happened in rapid succession. First, as I was looking at the sky, I realized I was looking at an infinity of time and space all at once. And then a word dropped into my head: “Oranios,” which is kind of the magic “Open, sesame” word in the novel, though I had no idea what it meant at the time. Simultaneously a scene arose in my head: a man on a pier having some sort of psychological meltdown and scaring the wits out of the people around him. Then I had to wait a while for some other idea to come around and attach to all this, which it did. That’s sort of how my books happen: you have idea X, and you’re waiting around for idea Y to collide with it, like atoms making a molecule. The other idea was one of the big reveals of the book, and I can’t really talk about it. But once that happened I knew the book had announced itself.

Given all the surprises in the story, how rigorously did you plot it out in advance?
This was a very challenging book to write because, as you point out, it’s not a linear plot: it’s actually recursive, where you come to a twist and you look backwards because it was absolutely going in this direction but you never saw it, this perfect misdirection happening. It was enormously difficult to do. That was one of my projects writing the book. When I write a novel I always try to do something I’ve never done before at the level of narrative artistry. But did I have a map? No. I knew the big moments—I knew what they looked like, I knew what they felt like, I knew what the sentences were. But figuring out exactly how to get there was tremendously challenging.

How did you develop the character of Proctor?
To an extent Proctor is a metaphor for certain experiences at midlife, this phase of life where you step back and you say, “Is this really my life? Is this really it?” So he’s suddenly caught up in more celestial questions about what’s happening. I was drawing from some of my own experiences: 10 years ago, I got a very scary diagnosis and there was a period of time that was tremendously uncertain. This has all worked out just fine, but my mind was sort of nudged toward larger questions. Something comes along and taps you on the shoulder and says, “Guess what? Not only can you not take it with you, you can’t take you with you. Nothing here is permanent. Nothing here is what you thought it was. You don’t really know what’s going on at all.”