The Decameron is a collection of novellas by Giovanni Boccaccio that was written in the 14th century but remains relevant to the themes of decadence and the fin-de-siècle. The book consists of 100 tales told by a group of young people who have fled Florence to escape the Black Death. These stories explore various aspects of human nature, including love, lust, deceit, and the pursuit of pleasure. Boccaccio's Decameron is a timeless work that delves into the complexities of human desires and serves as a precursor to the decadent literature of the fin-de-siècle.