She remembers sitting in an armchair with Agnes reading the nature encyclopedia, screaming over and over again, first with fright, then glee, when they turned to the magnified pictures of spiders. Her sister read that spiders have book lungs, which fold in and out over themselves like pages. This pleased Isabel immensely. When she learned later that humans do not also have book lungs, she was upset. Book lungs. It made complete sense to her. This way breath, this way life: through here.