Although Mendelssohn was most famous during his lifetime as a composer, virtuoso pianist, and conductor, he also enjoyed an enviable reputation as a highly skilled organist. The instrument had fascinated - one might almost say mesmerized - him from earliest youth, but aside from a year or so of formal training at the age of about twelve or thirteen, he was entirely self-taught. He never held a position as church organist, and he never had any organ pupils. Nevertheless, the instrument played a uniquely important role in his personal life. In the course of his many travels, whether in major...