Mark Twain 
A horse’s tale [EPUB ebook] 

A Horse's Tale is a novel by Mark Twain (Samuel Clemens), written partially in the voice of Soldier Boy, who is Buffalo Bill's favorite horse, at a fictional frontier outpost with the U.S. 7th Cavalry.
Harper's Magazine originally published the story in two installments in August and September 1906. Clemens wrote the story after receiving a request from actress Minnie Maddern Fiske to assist in her drive against bullfighting.[2] Harper's published the story as a 153-page book in October 1907.