Commissioned by violinist Jennifer Koh as part of her "Limitless" recital project collaborating with composer-performers, Tyshawn Sorey's "In Memoriam Muhal Richard Abrams" for violin and glockenspiel is itself dedicated to the memory of another composer-performer, the titular pianist and cofounder of the Association for the Advancement of Creative Musicians. The music of Sorey's friend and mentor, in particular Abrams' large-scale piano piece "Young at Heart", taught the younger composer to recognize the boundary between improvised and notated music as irrelevant, in certain ways, to the kinds of music Sorey wanted to make. "In Memoriam Muhal Richard Abrams", whose complex rhythms unfold slowly over the course of seven minutes, was premiered by Koh and Sorey at Brooklyn's National Sawdust venue in March of 2018. This score (two copies required for performance) is presented in landscape format.