The Hunchback of Notre Dame is the English title of Victor Hugo's 1831 novel, Notre-Dame de Paris. Translating the title seems to have been a difficult process; before Hunchback was settled on (more or less by attrition), the book was published under many different names in English, including Esmeralda, the name of the novel's ill-fated female protagonist. I read a translation as penance for seeing the Disney animated version noded in great detail above, but that was years ago, so I'll leave a detailed book review/literary analysis to someone who's interacted with the text more recently (hint, hint: it's even online in several places, kids!) Most of what I have to share is a bit of history about the book itself.
The Book
Fun fact: Goethe hated Hugo's book with a passion, calling it "the most dreadful book ever written." (In French, because that somehow conveys a deeper disgust: "C'est le livre le plus affreux qui ait jamais été écrit.") But I digress.
The book itself is an odd mix of melodrama and history; set in 1482, at the end of the Hundred Years' War, it devotes entire chapters to detailed descriptions of the city of Paris as it was at that time. These historical and architectural passages were apparently intended to appeal to male readers, although the author addressed Notre-Dame de Paris to female readers, because of its melodramatic and sentimental plot. The plot, just because a little synopsis is in order, is about a tangle of relationships: Quasimodo, the title character, is a deformed outcast who hides in the safety of the cathedral, where he serves as bell-ringer (the work has left him deaf). His protector is deacon Claude Frollo, whose forbidden love for the beautiful gypsy girl Esmerelda brings about several tragedies. Esmerelda is accused of witchcraft, but is rescued at Frollo's orders by Quasimodo, who also falls in love with her. Esmerelda does not return Frollo's love, because she is enamored with Phoebus, a handsome Captain of the Guards. He turns out to be a heartless cad, but unfortunately Esmeralda is accused of his murder. You see where this is going? Everybody dies unhappy, except Phoebus, who dies because he was a creep. I apologize to purists for my gross oversimplification of the material.
The History
Hugo really struck gold with the setting of his book: he was writing at the height of Romanticism, a period known for its admiration of Gothic architecture, of which the cathedral of Notre Dame in Paris is one of the most famous examples (and rightly so). At the time of his writing, Notre-Dame had been falling into disrepair and ruin; the French Revolution had taken a similar toll on holy sites throughout France, as the revolutionaries sought to break the power of the Church which had intertwined with that of the monarchy. The publication of Hugo's book called attention to the sorry state of the cathedral, and within a relatively short time spawned a movement to restore the building to its former glory. A contest was held inviting architects to submit plans for the restoration, and by 1845 the project was underway. Notre-Dame's restoration was completed in 1864.
Film versions
Film versions of Victor Hugo's book were well summarized by "The Signature of a Lion", an exhibition about Victor Hugo and Notre Dame at the cathedral in Paris:
The most admired film version is the one by William Dieterle with Charles Laughton (1939), but the most faithful adaptation is the film Jacques Prévert wrote for Jean Delannoy (1956); the most saccharine, the cartoon version by Disney Studios (1996).
Other films based on the book include 1911's Notre Dame de Paris/The Hunchback of Notre Dame by Albert Capellani and Esmeralda, a 1922 British film (IMDB didn't know much about either of these). There was also a 1923 version with Lon Chaney in the starring/title role, and several made-for-TV movies and straight to video releases.
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Sources
"The Signature of a Lion" exhibition on Victor Hugo and Notre-Dame de Paris at Notre Dame cathedral in Paris, 2 August 2002.
http://us.imdb.com/Tsearch?the+hunchback+of+notre+dame