Theatre of Eternal Music

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. The core of the group consisted of Young (voice, saxophone), Tony Conrad (violin), Marian Zazeela (voice, lighting), and John Cale (viola), with additional participants including Angus MacLise, Terry Riley, Billy Name, Terry Jennings, Jon Hassell, Alex Dea, and Jon Gibson. The group's self-described "dream music" explored drones and pure harmonic intervals, employing sustained tones and electric amplification in lengthy, all-night performances.

Archival recordings of the group's influential 1960s performances remain in the possession of Young, but none have ever seen official release. A dispute over compositional credit between Young and other members (namely Conrad and Cale) resulted in Young's refusal to release any of the material. Nonetheless, a bootleg recording of a 1965 performance was controversially released in 2000 as Day of Niagara. Other bootlegs of the group have appeared online via file-sharing sites.