Les Misérables , colloquially known in English-speaking countries as Les Mis , is a sung-through musical based on the 1862 novel of the same name by French poet and novelist Victor Hugo. The musical premiered in Paris in 1980, and has music by Claude-Michel Schönbergand original French-language lyrics by Alain Boublil and Jean-Marc Natel. An English-language libretto was written by Herbert Kretzmer. The London production has run continuously since October 1985, making it the longest-running musical in the West End and the second longest-running musical in the world after the original Off-Broadway run of The Fantasticks.