Includes primarily manuscript and published scores by various composers, plus a scattering of other material (personal photocopies, composer program notes and addenda, business cards, etc.). Much of the material was sent to the Kronos Quartet by individual composers and publishers to highlight their works and publications. The music is primarily for string quartet with other works for various combinations of voices and/or instruments. Some of the scores have performance markings written in by members of the Quartet. The collection was donated by the Quartet, in 1990 and 1999.