We never love anyone. Not really. We only love our idea of another person. It is some conception of our own that we love. We love ourselves, in fact.

My novels are often about people who are in love or attracted to each other.

When it's mutual, a man and a woman know, instinctively, wordlessly. They may do nothing about it, but the knowledge of that shared desire is out there in the world - as obvious as neon, saying: I want you, I want you, I want you.

With film, you have very limited tools to convey subjectivity - voiceover, the camera's point of view, good acting - but even the very best actor in the world is crude by comparison with what you can do in a written paragraph.

It's true: lives do drift apart for no obvious reason. We're all busy people,we can't spend our time simply trying to stay in touch. The test of a friendship is if it can weather these inevitable gaps.

Film is a medium of clear lines and broad strikes - which can be fantastic - but compared to the subtleties and nuances of a novel, it doesn't even get close.

Do we change every time we have a new encounter? Are we endlessly mutable? I think these are fascinating questions: it's a rich vein to tap, and I don't think I have exhausted it fully yet.