The gauzy, indistinct term “impressionism” is tossed around a lot with Debussy (not that he cared for it himself). So let's state things more clearly: this composer's appetite for new textures—and his skill with lush, harmony-stretching orchestrations—helped launch the 20th century in Western music. Popular with both lay audiences and specialists, his influence is still considerable: jazz players study the dissonances of the later Préludes, while the Nocturnes look ahead to some of Meredith Monk's orchestral work. And you can't get the decadent orchestra Notations of Pierre Boulez without Jeux. Be sure to go beyond La Mer to discover rich works like Debussy's opera Pelléas et Mélisande.