Charles Foster set out to know the ultimate other: the non-humans, the beasts. And to do that, he tried to be like them, choosing a badger, an otter, a fox, a deer, and a swift. He lived alongside badgers for weeks, sleeping in a sett in a Welsh hillside and eating earthworms, learning to sense the landscape through his nose rather than his eyes. He caught fish in his teeth while swimming like an otter; rooted through London garbage cans as an urban fox; was hunted by bloodhounds as a red deer, nearly dying in the snow. And he followed the swifts on their migration route over the Strait of Gibraltar, discovering himself to be strangely connected to the birds.