Like every writer, I'm drawn by unlikely juxtapositions, precisely-dated and once-only collisions between people from different worlds.

For myself, the only way I know how to make a book is to construct it like a collage: a bit of dialogue here, a scrap of narrative, an isolated description of a common object, an elaborate running metaphor which threads between the sequences and holds different narrative lines together.

What fascinates me are the turning points where history could have been different.

Like a historian, I interpret, select, discard, shape, simplify. Unlike a historian, I make up people's thoughts.

The experienced writer says to the anguished novice: 'Just do it; get something, anything, on to the screen or page, just establish a flow of words, and criticise them later.' You give this advice but can't always take it.

Much historical fiction that centers on real people has always been deficient in information, lacking in craft and empty in affect.