What is it to be human? This question, as in Birdsong, is at the heart of "Human Traces". The story begins in Brittany where a young, poor boy somehow passes his medical exams and goes to Paris, where he attends the lectures of Charcot, the Parisian neurologist who set the world on its head in the 1870s. With a friend, he sets up a clinic in the mysterious mountain district of Carinthia in south-east Austria. If The Girl at the Lion d"Or was a simple three-movement symphony, Birdsong an opera, Charlotte Gray a complex four-movement symphony and On Green Dolphin Street a concerto, then Human Traces is a Wagnerian grand opera.