"Glasspieces" was originally performed in 1983, "In The Upper Room" suite premiered in 1986, and both accompanied a ballet performance. This is the only place you can find the ensemble version of the "Funeral" from 'Akhenaten', which was a show-stopper from Glass's ensemble concerts of the mid-80s. There are a number of musicians on both pieces and "In the Upper Room" includes conductor Michael Riesman on piano and synthesizers. In addition to the keyboardist, there are a number of string, brass, and woodwind players. Although nearly all instrumental music, the additional voice (Dora Ohrenstein) on both pieces gives this works a very nice touch.