Admittedly a rather long read though much more interesting once you get past the first couple of chapters. 
 The story is focused around the psychiatrist Andrew Marlow and his most recent patient, the artist Robert Oliver whom attempted to attack a painting in the National Gallery and whom has an obsession with a stack of letters. To understand and help Robert, Andrew delves into the past--both Robert's and Beatrice de Clerval's--to learn what has caused this obsession. 
 It does drag at times and unless you possess the strength of will to press through it, I wouldn't recommend it as it is rather sizable. Overall though, it is elegantly written.