Bel-Ami by Guy de Maupassant.
I've read some of Guy de Maupassant's short stories before (and I could never forget The Horla), but Bel-Ami (1885) was the first novel I'd read by him. The fact is, I don't remember enjoying a novel or getting so excited by it since the first I read Germinal by Émile Zola, which, coincidentally, came out the very same year as Bel-Ami. Bel-Ami is an incredible work!
It's about Georges Duroy, the 'bel-ami' of the title, who we meet in the first chapter rather down on his luck. He was a soldier recently returned from Algeria, and has only 3 francs in his pocket. He then meets a fellow soldier, Charles Forestier, who changes his life. Forestier is an editor at La Vie française and he encourages Georges to join him there. He lends Georges money for some smart clothes and invites him to dinner the following night to meet the owner of the paper. Georges is quickly commissioned to write about his experiences in Algeria but, when writers' block strikes (not for the first time) Forestier's wife Madeleine does the bulk of it for him. From here Georges steadily builds himself up and gains the reputation of being a good journalist with Mme. Forestier's help (and, to a lesser extent, that of his mistress Mme de Marelle), and becomes an active member in politics and rises up in the ranks of journalism and society. Following the death of Charles Forestier he then marries Madeline and, at her request, adopts the name Georges Du Roy de Cantel.
The novel continues to depict Georges rise along with various intimate (and complicated) relationships with women. It reminds me a little of Émile Zola's The Kill insofar as we have a prominent political figure whose life is rather unsavoury. Though Georges is an excellent character, he's far from likeable and we see how his lack of morals and insatiable appetite for power propels him to his high position that was not really earned. Like Zola, Guy de Maupassant paints a powerful and vivid picture of Paris in the late 19th Century and I do think Bel-Ami is a remarkable achievement. It certainly makes me want to revisit his short stories and read his other novels, although, sadly, there aren't that many.