Dun Lady's Jess
Dun Lady's Jess is a the first book in Doranna Durgin's Changespell Saga trilogy. It was published in paperback by Baen Books in August 1994 with the ISBN 0671876171. It tells of a courier rider and his horse, flung from their magical world into our own, and separated. The magic also changed the horse - Jess - who must come to terms with her new, strange human shape, while trying to reunite with her beloved rider, and remain safe.