I played one of the movments in band in high school, so I thought I'd write about another movement.
The movement is called Adagio Contemplativo so there is some sense of reflection and melancholy but this doesn't mean there aren't huge loud climaxes with jarring dissonances, hey this is 20th century music.
The piece immediately begins with the main motive in the low strings and the breaks are filled in by dissonant chords in the woodwinds followed by a resolution with repeated notes in the flute and celeste. This is a very interesting combination of instruments not commonly seen but the two sounds fit in quite nicely with each other. The melody moves to the middle strings and has a feel of contemplation in a minor feel. The parts begin to fragment also with different string instruments doing different lines reaching a climax of lots of dissonance with a big timpani roll followed by the decrecendo again.
At this point the horns take over the melody for a while followed by the woodwinds having it with some suspended cymbal rolls. Then the mood becomes slightly more frantic with the woodwinds doing scattered notes with the oboe (maybe english horn) having the melody. This is followed by a really cool addition of the harp doing big sliding glissandos that kind of sound like what I think of as the "time warp" cliche with the trumpets holding the melody. This eventually reaches another really big climax. This eventually rises to what i think is a big IAC with lots of dissonances that block true feelings of cadence followed by another similar climax a little later on followed by the complexity falling down again.
This leads to a section very much like the beginning with the low strings taking the melody followed by the horns and woodwinds taking it before the music eventually leads to a bright major sounding woodwind chord that dies away with the horns holding a chord with a major feel.