Most underrated composer of 20th Century?

Villa Lobos is certainly right up there, his string quartets were a big surprise to me.

Problem I have with Ellington is you never know what was written by Strayhorn.
Sorta like Beethoven publishing Schubert work as his own.

Western classical music has always had a heavy European bias, for clear historical reasons. Are the most underrated composers of the 20th century likely to still be mined in those waters?

Mapman is asking the question that - as a person whose interest in classical music is equal parts aesthetic and anthropological - probably interests me more than any other.

I would speculate that increased appreciation of alternative musical languages is probably an inevitable result of the shrinking world around us. I'd also expect that compositions employing microtonal scales (whether from Asia or from Western composers who borrowed the approach) will gain more attention from critics and scholars. The evolution of the legacy of Harry Partch, et al will be interesting to watch.

Similarly, it will be interesting to see how the big names of the second half of the century hold up. Will Phillip Glass end up as the most underrated composer of the century or the most overrated? Which also raises the question of opera and its place in this question. Where does Alban Berg belong?

I'm not really proposing any candidates here, just following up on Mapman's interesting observation.

Straight up, Ellington claimed works he did not write.

I try to stay away from threads like this, as a professional musician, however I can't resist commenting that Philip Glass will NOT be considered underrated. He is very likely to be considered highly overrated, in fact he is so now by a great many. I like to call him the Andy Warhol of music - pop art at best. Minimalism in music is almost the same thing as Warhol's pop art, except Warhol had to work harder, because he actually drew each part of those paintings over and over again. All Glass has to do is come up with a few different chords and textures, and that's it. Pretty much anyone with basic compositional training could write that stuff. Most of his music would be intolerable, because of its length, without films that go with it. Some go as far as to call minimalism in general an intellectual cop-out. In the case of Glass in particular, I would agree. There are a couple of minimalists who have written some interesting stuff - Steve Reich is the best of them.