Engaging horse tale, War Horse, by Michael Morpurgo. New York: Greenwillow Books. 148 pp. $9.50. Ages 11 and up.

It's hard not to love horses, or at least admire them, and author Michael Morpurgo is no exception. If you don't like horses, don't bother with this book. But if you loved - and agonized - through ''Black Beauty,'' you will enjoy this story, told in the same first-horse style.

''War Horse'' details the life of Joey,''a splendid red bay with a remarkable white cross emblazoned on his forehead and with four perfectly matched white socks,'' A spirited, yet gentle animal, he finds himself thrust - or rather, sold - into the middle of World War I as a British Army horse. In the process of tracing his life from foal to retired veteran, the novel becomes as much a paean against war as the chronicle of a life caught up in it.

As with most war stories, there are occasional graphic descriptions of war, which may distress some readers.