Do you know that feeling you get when you don't brush your teeth before going to bed? It's not just that your teeth are fuzzy, but your day seems incomplete, like you've forgotten to lock the door or feed the cat.

That's how I feel when I don't read before bed. I have to pick up a book, even if it's 3 a.m. and I'm exhausted from a night out. Even if I have the flu. Even if the only thing in the house is a magazine two years out-of-date. Even if I manage only two pages before the words start to blur.

I don't know why I have to do this. Maybe reading provides a stepping-stone from the conscious world to the dream world. Books, especially novels, make me let go of myself and enter willingly into another place. I bet I sleep better because I let go. More practically, bedtime is also when the phone isn't ringing, the computer is switched off, and my family doesn't need me.

When I was a girl, I used to check out a stack of books from the library every week, and I would lie on my bed reading them one after the other, like munching through a bucket of popcorn. I miss that part of my childhood. Now I write books for others to lose themselves in, and that eats up most of my time—except for those precious moments before sleep.

Tracy Chevalier's new novel is The Lady and the Unicorn . The film based on her book Girl with a Pearl Earring is out now.

What's on Tracy Chevalier's Bookshelf? Read more!