Though a relatively slim volume with lean yet lyrical prose, What Is a Dog? is a book with colossal emotional heft. Beginning with how author Chloe Shaw, her husband, and their children recently said good-bye to and then mourned their beloved senior dog, Booker, Shaw presents a memoir told through relationships with the canine companions that walked beside her at each stage of her life: from her childhood comforter, Agatha 2, to Otter, the puppy that helped her family to heal and grow even closer together after the passing of Booker. "A dog is the predisposed portal away from any anguish there is," Shaw memorably declares at one point. This is a book that perfectly captures not just the deep pains, but also the even deeper pleasures, of having a dog steal your heart.