Opera has been around ever since the late 16th century, and it is still going strong in the sense that operas are performed around the world at present, and known by infinitely more persons than just those who attend performances. On the other hand, it has enjoyed periods in the past when more operas were produced to greater acclaim. Those periods inevitably have pride of place in this Historical Dictionary of Opera, as do exceptional singers, and others who combine to fashion the opera, whether or not they appear on stage. But this volume looks even further afield, considering the cities which were and still are opera centers, literary works which were turned into librettos, and types of pieces and genres. While some of the former can be found on the web or in other sources, most of the latter cannot and it is impossible to have the whole picture without them.