Ghostlove.
(Book)

William Rook is an occultist living in a haunted brownstone in upstate New York. There he has encountered many marvelous and confusing occurrences: an ever-shifting bloodstain on his study floor; his own cynical doppelgänger; a three-winged pigeon; and, most importantly, June, the ghost living in his bedroom. June is everything William has hoped to find--by turns playful and serious, petulant and flirtatious. But she is also secretive and sad, trapped in a hopeless limbo, her past a mystery she won't reveal. William becomes determined to help her, engaging daily in a series of experiments, rituals, and spells. But success means letting June move on, and the more William learns of her past and present, the less sure he is that he's ready to let her go.