The Dark Lady: A Romance of the Far Future

From the back cover of the Tor first edition: "Who is the Dark Lady? Her portraits span the course of human history, yet she remains forever young, forever seeking... An enigma of the eternal night, she calls men to great deeds... and to their deaths. Not only humans hear her siren's song - to the alien art historian Leonardo, the Dark Lady is much more than a haunting spectre - she is the key to his salvation. He will risk much to unravel the mystery of this most compelling phantom. But the Dark Lady guards her secrets well. And all Leonardo has to aid him is his innocence - it will not be enough."