Don't get too comfortable with this disc's opening minutes, which sound convincingly like a well-tuned consort of viols performing two short pieces by Machaut and Tye. These two works from the 14th and 16th centuries quickly give way to a piece from 1997 by David Lamb. Then come Arvo Part, Harry Partch, John Cage, and even Moondog, a.k.a. Louis Hardin. Additional instruments come and go- -harmonium, bagpipe, zhong ruan, nyckelharpa, drum--all of which complement and enhance the string sounds. Later, we hear music by Hildegard von Bingen, Perotin, and even Purcell. Most of the selections from early composers are arrangements by the Kronos Quartet and others, but it's a tribute to the recording's producers that in spite of the music's diversity, everything works together to make a coherent, cohesive, intellectually, and musically challenging program. --David Vernier