Puccini’s melodrama about a volatile diva, a sadistic police chief, and an idealistic artist has offended and thrilled audiences for more than a century. Critics, for their part, have often had problems with Tosca’s rather grungy subject matter, the directness and intensity of its score, and the crowd-pleasing dramatic opportunities it provides for its lead roles. But these same aspects have also made Tosca one of a handful of iconic works that seem to represent opera in the public imagination.