Composer Michael Gordon and Kronos Quartet have worked together since 2001—Gordon’s visceral, inventive music is perfect for a quartet that continually champions the new. This album presents their four finest collaborations. Potassium is a breathless, charged masterpiece that pits distorted, sliding strings against driving chords. In The Sad Park, Gordon stretches, compresses, and morphs young children’s responses to 9/11, finding the most poignant, heartbreaking music within. Clouded Yellow dazzles in its depiction of migrating butterflies while Exalted, which sets lines from the Jewish Kaddish prayer, fizzes with defiance.