What Could Have Been: Even after he started shopping the manuscript of the novel around to publishers, Giuseppe Tomasi di Lampedusa was still having ideas for additional chapters that would have filled in some of the characters' activities in the 1870s and 1880s. In the event, however, he died before completing any of these additional chapters, so the novel was published as submitted (although following the novel's success some editions do include surviving fragments as bonus material).
Write Who You Know: Giuseppe Tomasi di Lampedusa was himself the last in a Sicilian noble line, and the House of Salina is a fictionalised version of his own family. Shortly before his death, he wrote a letter to a friend outlining who the key people and places are based on. He stated that many of the details of his portrait of Don Fabrizio were drawn directly from his great-grandfather, Don Giulio Fabrizio Tomasi. Other characters are more fictional: Tancredi is a combination of attributes from several different people, and Tomasi di Lampedusa made a point of not saying if Tancredi's wife Angelica (who is, along with her family, not depicted in an entirely flattering light) was based on anyone in particular.
The film
Completely Different Title: In France, the film was released as The Cheetah. Incidentally, the English title is itself entirely different. The italian title is Il Gattopardo and it was intended to refer to the Serval an obscure member of the Big Cat family but which was mistaken in other countries for what they considered more representative members of that species type.