The Shell House — Linda Newbery

Greg's casual interest in the history of a ruined mansion becomes more personal as he slowly discovers the tragic events that overwhelmed its last inhabitants. Set against a background of the modern day and the First World War, Greg's contemporary beliefs become intertwined with those of Edmund, a foot soldier whose confusion about his sexuality and identity mirrors Greg's own feelings of insecurity.

This is a complex and thought-provoking book, written with elegance and subtlety. It will change the way you think.