Stendhal was forty-seven when his first major novel, Le rouge et le noir, was published in 1830 (although a little known and unremarkable book called Armance did precede The Red and The Black).  This tale of the young Julien Sorel, takes some dedication to finish and is best devoured in the original French.  Often cited as one of the top ten best novels of all time, Le rouge et le noir is situated in the middle of the restoration of the French monarchy after the fall of Napoleon, whom Julien greatly admires (in secret of course). This young idealist is naïve and faced with the choice of entering religious orders and wearing the black robes of the clergy (le noir) or following a military career (le rouge). Julien Sorel ends up doing both badly, with his adventures punctuated by a number of romantic encounters along the way.
The novel shows how the ideals of “liberté, égalité, fraternité” created by the revolution of 1789 were quickly abandoned in the 1830s. The stifling remains of the restored aristocracy and clergy remain in full force, with young Julien confronted by the realities of the French class structure which looks down on his dalliances with the women of a higher station, either in his own small country town in the Jura, or in the salons of nineteenth century Paris.
The Stendhal style in this novel has spawned a number of PhDs in the last 150 years.  Of interest, this novel shows some unusual flourish for a book published in the 1830s. These include a few “intrusions†of the author and discussions between the editor and the author, with the former remonstrating Stendhal for stopping his characters from engaging in political debate, as any real 1830s French person would. The style also moves away from the usual tiresome Balzacian photographic descriptions of scenery, and allows the reader to view the world through the flawed perspective of Julien’s perception. The Stendhal style of writing is therefore known as “subjective realism†(term invented by Georges Blin in “Stendhal et les problèmes du romanâ€). The rhythm of the novel is also an unusual innovation for the 1830s, sentences are short (for a French novel), the dialogues are quickly delivered and Stendhal takes us from external descriptions to Julien’s inner monologue, sometimes in the same sentence.   With his comparative style, Stendhal places the reader firmly into the events of 1830s Paris, either through the political fights between the “ultras†and the “liberalsâ€, or the religious skirmish between Jansenists and Jesuits, or Stendhal’s admiration for London society juxtaposed to his condemnation of the hypocrisy of the “comédie perpétuelle†of Paris.
Le rouge et le noir is worth a single read if you get half a chance. Nevertheless, with the publication of so many great novels since 1830, Stendhal’s work has probably fallen out of favour, and Le rouge et le noir is unlikely to make any new all-time top ten.
In terms of film adaptations, the 1997 french movie version of the Red and the Black with Carole Bouquet as Mdm de Renal brings the story down to a TV soap-opera. Although I have never seen the 1954 version with french actor Gerard Philip as Julien Sorel, I understand that this version is the best film adaptation. The original cinematic version was a three and a half hours long film, which you can now enjoy through the medium of a 2010 remastered Gaumont DVD edition, unfortunately only available in France.