Most underrated composer of 20th Century?

Its a good point that most of these guys are highly regarded in knowledgeable circles but relatively unknown to the masses. Just goes with the turf I suppose.

Frogman,

Excellent comments. some of the most influential composers were certainly not the most popular (e.g.,Berg, Webern), particularly measured by current fashion.

I like the composers you mentioned, particularly Frank Martin (mainly for choral works) and Thomas Ades. I am a big fan of John Adams too (his violin concerto is one of the finest written).

There are so many that are worthy of being heard. My personal list of favorites include:

Tippett, Alwyn, Walton, Turnage, MacMillan, Lindberg, Tuur, Jongen, Olsson, Boulez, Dutilleau, Milhaud, Durufle, Varese, Boulez, Gubaildulina, Myaskovsky, Tubin, Penderecki, Zemlinksy, Enescu, Dohnanyi, Penderecki, Ligeti, Nono, Bloch, Ruggles, Babbitt, Ives, Beach, Crawford Seeger.

Some that either did very few works or specialize in just certain forms that I like are Whitacre (vocal works) and Partch (Delusions of the Furies being a personal favorite).

True Frogman I thought of that when starting this post but could not have expressed it as well as you have.

I remember being frozen like a deer in the headlights. when I first heard Martin's Violin Concerto on the radio back in the seventies. I did finally get a copy of it with Martin conducting, but his music then was on Swiss labels you couldn't find in the days before Amazon etc.

Glazunov isn't much done in the USA, but he is a concert staple in much of Europe.

Exactly Frogman and Mapman, it's so hard to get a grip on what "underrated" means. My musically well educated colleagues roll their eyes with ennui at the mention of most composer's that the average classical listener has never heard of, so it is all relative. Plus, I agree with earlier statements about cultural prejudices coming into play. I happen to really like Takemitsu & Minoru Miki, but they don't seem to resonate with a large number in the western world. Also like Rautavaara, Lindberg, Kokkonen, and Saariaho, but general appreciation for Scandanavian composers ends with Sibelius and Grieg. Then there are "could have been greats" like Gideon Klein whose life was cut short by a Nazi concentration camp and Karl Amadeus Hartmann whose composing career was pressured by his duties as an administrator resurrecting German musical culture after WWII. Paul Hindemith deserves a place at the table of underrated greats as well IMO.

Amen, Photon46, the amount of fascinating modern music coming out of Finland alone beggars belief.
Not to mention half the conductors in the world are Finnish.