I can't keep it straight, so I'll just give it a new title.
Arnold Schoenberg managed to set the musical world on its ear, in the same way and at the same time a bunch of painters were doing the same thing in the visual arts. Generally called "modernism", it was nothing more than innovation, taking the next logical step. Sometimes his music is considered "atonal", which it really wasn't. There just wasn't the same kind of harmonic order that earlier music had. His "12-tone" ideas are interesting, and would be picked up by jazz musicians later in the century. Here's an excerpt from his Piano Concerto 42, with Mitsuko Uchida on piano:
Another excerpt, from his Chamber Symphony, op. 9, from 1984, with Erich Leinsdorf conducting.
I think Glenn Gould is the perfect interpreter of Schoenberg, if for no other reason than he goes well with being a coke-head. Here he is with Yehudi Menuhin on violin, playing Fantasie, op. 47.