sentences:  Kennedy co-founded and led the new music ensemble Essential Music, a group of flexible instrumentation which from 1987 to 2001 led a broad traversal of the American Experimental Tradition and presented over 100 concerts.During this period Kennedy had an association with John Cage, reviving a number of Cage's early works, including restoring the radio play "The City Wears a Slouch Hat".Kennedy also led the rediscoveries of the music of Johanna M. Beyer and William Russell in performances and recordings by Essential Music.