In "Horse Nation" Martino writes about the equine heroes and the fallen, the defiant ones and the teachers & healers. There was Casey, the blood bay, who jumped a teenage girl over her mother's sports car as a rite of passage; Icy, a deep black mare, strong and independent, embodied the circle of life; and The Corinthian, a gray gelding, defined what it is to be a champion. Martino also writes of the horse people---riders, grooms, coaches, and students---who...