I can't imagine a man really enjoying a book and reading it only once.

Rereading is the proof that a book was truly loved. Lewis suggests that a story worth enjoying is not a puzzle whose pleasure is used up once the solution is known. If we read only to find out what happens next, nothing is left once we know. A book that delights us offers more than its plot: the texture of its sentences, the atmosphere of its world, the company of its characters, and details we were too hurried to notice the first time.

This rests on a view Lewis develops in An Experiment in Criticism, where he says good readers are marked by how they receive a book rather than by which books they read. Casual readers consume a text and discard it, while those who care about a book come back to it. Behind this lies an older belief that great works are inexhaustible, and that we change over time, so the same pages meet a different person each time. The line is widely credited to Lewis, and I know of no serious dispute about it.

Today, someone could take a novel that moved them years ago and read it again this winter, slowly, perhaps with a pencil in hand. Instead of chasing a reading tally, they might find that the old book has changed because they have.