Just finished Kate Morton's "The Distant Hours," and loved reading this in the afterward:

The Distant Hours started as a single idea about a set of sisters in a castle on a hill.

I love that. That a novel comes from a single idea — even though I know it as well as anyone. "Rattled" started as a column I wrote for The New York Times. "Cars from a Marriage" sprung from a remark in couples' therapy. My next idea, and I am working on it, could be something equally simple. Maybe I have even stumbled on it already.