The White Horse by Eli Goodman, MD
Based on a real-life revelational experience that is described in the substantial Afterword section, The White Horse teaches that one should not judge another by superficial characteristics. In a rural setting whose exact time and setting are purposely undefined, a family of four young children and their parents rejects a horse because of his skin color. The horse initially resigns himself to his outcast status, but when the children find themselves in danger, he emerges as a confident rescuer. The horse's heroic act proves to the family, and to the horse, himself, that their preconceived prejudices about him were, for many reasons, entirely wrong.