Suite for Microtonal Piano (1978) is a suite for specifically microtonally tuned piano(s) by Ben Johnston written in 1977 (see also just intonation). According to Bob Gilmore the piece, "take[s] extended just intonation well beyond the point reached by Harry Partch."[1]
"The piano is tuned to a selection of overtones from the fifth octave of the harmonic spectrum of C. All octaves are tuned in the same scale....The lowest C (33 Hz.) can be used to tune the scale by ear. In succession, touch the nodes producing the 3rd, 5th, 7th, 11th, 13th, 17th, [and] 19th partials. Then G, D; D, A; E, B; [and] B-flat, F; are just (beatless) fifths."[2]