What Is Not Yours Is Not Yours is cleverly built around the idea of keys, literal and metaphorical. The key to a house, the key to a heart, the key to a secret-Oyeyemi's keys not only unlock elements of her characters' lives, they promise further labyrinths on the other side. In Books and Roses one special key opens a library, a garden, and clues to at least two lovers' fates. In Is Your Blood as Red as This? an unlikely key opens the heart of a student at a puppeteering school. 'Sorry' Doesn't Sweeten Her Tea involves a house of locks, where doors can be closed only with a key-with surprising, unobservable developments. And in If a Book Is Locked There's Probably a Good Reason for That Don't You Think, a key keeps a mystical diary locked (for good reason).   Oyeyemi's tales span multiple times and landscapes.