My third published novel, like my first, originated with a trip I’d taken with my father. (He loves to travel, and has brought me on lots of astonishing trips over the years. We’ve visited every continent together, even Antarctica. The book for that one has yet to be written …)

When I was in my mid-twenties, we took a cruise from Venice to Istanbul, through the Greek Isles. Over the course of two weeks, we visited some of the most beautiful places on earth. As an aspiring author, I knew immediately that I had to set a story here.

And so I wrote a novel called Gravy, about a trio of horror novelists who take an identical cruise. The writers are engaged in a contest, unbeknownst to the rest of the ship, to see who can scare the other two the most. Needless to say, things go wrong and the contest gets all too real. The book was half-horror, half-suspense, and half-baked.

That novel remains unpublished. But when it came time to follow up A GAME OF SPIES, I’d been reading Eric Ambler and his tales of international intrigue set in Istanbul. The cruise popped immediately back into my mind. I dug up my old copy of Gravy and found that I had recorded first-hand, at some length, my impressions of the ship and the islands, of Venice and Istanbul.

A lot of ingredients went into the stew. Eric Ambler; my new wheelhouse of spy-thrillers-with-strong-female-antiheroes; and my interest in high-stakes physics, which had been reawakened while researching A GATHERING OF SPIES when I read Richard Feynman’s Surely You’re Joking, Mr. Feynman!

I was never much good at math or science. But the science-fiction reader in me has always been fascinated by the implications of relativity and quantum physics. My clumsy but sincere interest in big physics pops up in several of my books – most notably Deception and THE KOREAN WOMAN.

In high school, I had devoured the hard sci-fi of Larry Niven. I also loved a book called The Science in Science Fiction, by Peter Nicholls. I’d spend hours poring over brightly-colored pictures of black holes, of astronauts getting sucked past event horizons and turned spaghetti-thin. At sixteen, I tried writing a book about using black holes to achieve time travel. I entered a contest with the book, and didn’t even get an honorable mention.

With Eric Ambler on one side of my keyboard and Stephen Hawking on the other, I set to work. In Deception, the character of Keyes is driven by personal grief to take reckless chances with his particle accelerator. A brilliant scientist, sensing the danger, absconds with key formulae, and (relatively) innocent fish-of-water Hannah Gray finds herself caught in the middle.

As I was writing the book … 9/11 happened.

At the time, I lived in downtown New York, not too far from Ground Zero. I smelled the burning fires every time the wind changed. For weeks after the attack, my street was closed by the National Guard. I lived in fear – of the follow-up attack, the anthrax, the sniper, the suicide bomber. And I was also very, very angry.

My mind was already turning ahead. The next book must address 9/11. And it must try to balance my fear and my anger against my principles. THE WATCHMEN would be my darkest book yet.