To the well-honed investigative skills on display in her acclaimed biography of the Dionysian Robert Mapplethorpe, Patricia Morrisroe now adds the art of intuitive invention. Her first novel gives us the intractable genius of Ludwig (or as his Francophile contemporaries preferred, Louis) van Beethoven through the eyes of Countess Julie (or, as he preferred, Giulietta) Guicciardi, the dedicatee of his Piano Sonata No. 14, popularly as the “Moonlight” Sonata. The supporting cast listed at the outset goes on for pages, but never fear. Though researched to a fare-thee-well, Morrisroe’s fiction never lets atmospheric historic detail slow the swift pace of intrigue, politics, art, and sex. Can the HBO miniseries be far behind?