"O Napoleão de Notting Hill" by G. K. Chesterton is a novel published in 1904. Set in a future London around 1984, it tells the story of King Auberon Quin, a humorist who whimsically revives medieval customs in London's boroughs. When young Adam Wayne takes the king's joke seriously, he launches a real war to defend Notting Hill's independence. The novel blends satire and fantasy, exploring themes of patriotism, idealism, and the tension between humor and fanaticism in human nature.