On A 300-Year Generation Ship, The Erased Population Formed A Hidden Society Of Invisible Humans

On a generation ship three hundred years from anywhere, the missing rations have an official name: spoilage. Every quarter the census office writes off a few thousand people's worth of water and oats, stamps the box, and goes home to bed.

Then one census officer finds a man in a gray work shirt who has let himself into a family's quarters at the same minute every night for eleven years. His own files show he has found this stranger thirty-one times, closed every case as spoilage, and signed each one himself. He remembers none of them.<...