Few musicians who suffered from any kind of serious neuropsychiatric problems were able to create works that are still admired today. This new research will show that Frédéric Chopin, who reinvented piano music in the first half of the nineteenth century, was one of those few. He died in Paris aged only 39. While the somatic illness that killed him continues to generate speculation, his recurrent depressive mood swings have remained largely unexamined. A few neuropsychiatric publications make a simplistic effort to assign his emotional condition to a modern diagnostic category, e.g., temporal lobe epilepsy. Because it is impossible to prove such hypotheses, these studies are nothing more than erudite speculation. This chapter will instead incorporate the cultural and medical context of the first half of the nineteenth century in order to explore new possibilities for medical biographies of musicians.