The Kronos Quartet's commissioning and education initiative, developed by the nonprofit Kronos Performing Arts Association with lead partner Carnegie Hall. The project commissioned 50 new works for string quartet from composers around the world, designed expressly to train students and emerging professionals in the techniques of 21st-century repertoire. All scores, parts, recordings, and learning materials are available free of charge online. Now complete, the library has been used by musicians in more than 100 countries.