The Theatre of Eternal Music (later sometimes called The Dream Syndicate) was an avant-garde musical group formed by La Monte Young in New York City in 1962 in order to play and develop Young's compositional idea of The Tortoise, His Dreams and Journeys that involved improvisation within strict predetermined guidelines set by Young.

The first group (1962-1964) of performers consisted of La Monte Young, Marian Zazeela,