One might almost define this as a book of famous career horses, horses that through the centuries have been successful in their ways. First there's Bucephalus, charger of Alexander the Great; then steeds of such famous people as Caesar, El Cid, Joan of Arc, Cortez; trick horses, a highwayman's horse, horses who founded famous lines, horses who played their parts in history, race horses, a fire horse, a police horse, a rodeo horse, and so on. True stories all, succinctly told, the emphasis on their achievements rather than breeding or ownership. There's surprising unevenness in the quality of the telling -- in the interest. But practically any horse book has a sure market, and Paul Brown's drawings guarantee the additional fan market. Not in a class with Phyllis Fenner's collection of fictional horse stories, Horses, Horses, Horses.