The process of writing a book starts, for me, with a place in time that I find intriguing. I begin to do a little research -- if possible, with novels written at the time -- and then, if all goes well, I experience a kind of flash of complete understanding a few weeks later.

Every character, every setting, every moment of tension, choice, betrayal, and resolution comes into perfect focus. But only for an instant.

It’s as if I’ve been given this one chance to see how the book is meant to be, and the rest of the process -- the next year to year and a half -- is spent trying to recapture everything from that flash. Of course, I never manage to get it all, but that moment floats above and acts as a kind of guide.

Luckily, there are some bits that remain clearer than others. The general arc of the book -- the scenes that I know I have to get to -- usually seems pretty well fixed, but what happens between the scenes is left for me to discover.

And, I suppose, I prefer it that way. I’ve never been one for detailed outlines. I have the five or six scenes that stand out -- usually those when choices are made and, later on, when consequences play out -- but, aside from that, I like to see how the characters get from one place to another as they go.

It’s not as arbitrary as it might sound. Most pieces of fiction -- whether novels, films or plays -- are written in three acts. The best way I’ve heard to describe it runs as follows: In the first act, you take two sticks in either hand and place a rubber band around them; in the second act, you pull the sticks away from each other, making the rubber band as taut as possible -- another inch and it would snap; at the beginning of the third act, you stretch the rubber band just that bit further . . . and then let go.

Seeing structure in that way guarantees that conflict (or tension, or however you like to describe it) remains the driving force in the story. How that conflict manifests itself -- through characters, plot twists, etc. -- makes for the discovery.

The lengths of the acts can vary greatly. I’ve been surprised to find myself at the end of act one twenty pages into a book, and at other times, 100 pages in. Act three can be half a chapter, or three. Of course, having a good editor to tell you that an act is too long, too short, not fleshed out enough, etc. is crucial.

What resonates most strongly from the flash, however, is a connection with one or two of the characters. In my first two books, that wasn’t much of a stretch since the main characters were, to a greater or lesser degree, versions of myself. This time around, it was something entirely different, not just because the main character was someone I had to get to know, but because one of the characters wasn’t a person, but the city of Berlin. That might seem odd, but I’ve come to discover that place is as much a living, breathing thing as are the people who inhabit it.