Lord Mottistone (1868–1947) wrote My Horse Warrior, the story of the horse which carried him into the First World War. I am including this book on what is a website concerned with fiction, as not only is it a good story, but it is illustrated by Sir Alfred Munnings, who, as far as I am aware, illustrated just one horse book. Its author, Lord Mottistone (Jack Seely) served as an MP, and fought in the First World War. He became a Major General and commanded the Canadian Cavalry Brigade. He was mentioned in dispatches fives times, and was awarded five medals. After being gassed in 1918, he returned to England and domestic politics.
Finding the book
Early editions are not easy to find at all. If copies do turn up, they are rarely accompanied by their dustjacket. The reprint is readily available.
Bibliography: pony books only
My Horse Warrior, Hodder & Stoughton Ltd, London, 1934, illus Sir Alfred Munnings, 160 pp.
Reprinted several times
Reprinted as Warrior: The Amazing Story of a Real Warhorse by Jack Seely, Racing Post Books, 2011