A colleague and I were listening to a Bach violin concerto on the radio some years back. After a while my colleague said, “You know, there are a thousand Baroque violin concertos. Why is it that this one is just…better?” Johann Sebastian Bach wrote sonatas, concertos, suites, preludes and fugues, overtures, oratorios, and cantatas—music in all the major forms of the Baroque era, with the exception of opera.