It happens to nearly everyone. Years ago, on an afternoon whose colour has long since faded, in a book you no longer own, or on a brittle page of a newspaper, or in a fragment of audio that drifted through a half-listened conversation, you read a sentence. It might have seemed striking then, or perhaps it was perfectly unremarkable, merely one line among thousands scrolling past your eyes that season. You forgot it, as we forget most of what we read. The morning traffic swallowed it, the next...