Walter Piston - String Quartet No. 2 (Score Video) [1935]

Walter Piston's five String Quartets are a singular accomplishment of 20th century music. All are entrancing balances of form and expression. They often provided an outlet for Piston to be his most dissonant and contrapuntal, but also his most beautifully still and contemplative in the slow movements.
The 2nd Quartet followed after the 1st fairly quickly, with only a two year gap. I think the 3rd movement here especially is just amazing.
I. Lento - Allegro 0:05
II. Adagio molto e con espressione 10:28
III. Allegro giusto 18:19
Performance by the Portland String Quartet