In Squirrel, Nancy Castaldo shines new light on this familiar backyard mammal, exploring their staggering diversity (they're found on all continents but Antarctica) and the many surprising ways they shape our world, our communities, and our cultures. Each chapter explores an aspect of squirrels and their close and sometimes fraught association with humans: their importance to myriad ecosystems through sophisticated food-caching strategies; their introduction to nineteenth-century urban parks as adorable ambassadors for nature; their complicated global status as both invasive and endangered; their role as celebrated cultural icons and social media memes; and ultimately, why we must prevent population declines and protect their well-being while we can. Like other wildlife species, squirrels are increasingly stressed by climate change, and their speculative fate may foreshadow our own. The book includes a detailed bibliography, an exhaustive list of squirrel species and their status, and tips for coexisting peaceably with squirrels in our yards and neighborhoods. Chapters are introduced by exquisitely drawn historical illustrations.