What benefit is there for individuals or species as a whole, say, from dog bows or pig rolls? In “The Kingdom of Play,” David Tumi examines the nature, meaning, and mysteries of play behavior in a wide range of animals, from bumblebees to humans. The author transforms a wealth of serious scientific knowledge about the distinctive features of play, its prevalence in the animal kingdom, evolutionary history, and neurobiology, as well as the impact of play on individual lives and the developmental trajectory of species, into an engaging and cohesive narrative. Tumi presents play as far from a unique product of natural selection for humans and at the same time as a rich provider of material for it.