Stephen Michael Reich ( RYSHE; born October 3, 1936) is an American composer best known as a pioneer of minimal music in the mid to late 1960s. Reich's work is marked by its use of repetitive figures, slow harmonic rhythm, and canons. Reich describes this concept in his essay "Music as a Gradual Process" by stating, "I am interested in perceptible processes. I want to be able to hear the process happening throughout the sounding music." For example, his early works experiment with phase shifting, in which one or more repeated phrases plays slower or faster than the others, causing it to go "out of phase." This creates new musical patterns in a perceptible flow. His innovations include using tape loops to create phasing patterns, as on the early compositions It's Gonna Rain (1965) and Come Out (1966), and the use of simple, audible processes, as on Pendulum Music (1968) and Four Organs (1970). Works like Drumming (1971) and Music for 18 Musicians (1976), both considered landmarks of minimalism and important influences on experimental music, rock, and contemporary electronic music, would help entrench minimalism as a movement. Reich's work took on a darker character in the 1980s with the introduction of historical themes as well as themes from his Jewish heritage, notably Different Trains (1988). Reich's style of composition has influenced many contemporary composers and groups, especially in the United States and Great Britain. The critic Andrew Clements has suggested that Reich is one of "a handful of living composers who can legitimately claim to have altered the direction of musical history".

Six Pianos is a minimalist piece for six pianos by the American composer Steve Reich. It was completed in March 1973. He also composed a variation for six marimbas, called Six Marimbas, in 1986. The world première performance of Six Pianos was in May 1973 at the John Weber Gallery in New York City. The European première took place in January the next year in Stuttgart, Germany. Reich's idea was originally for a piece titled Piano Store that could be played on all the pianos in a piano store. A friend in New York gave him and his fellow musicians access to the Baldwin Piano and Organ Company's premises during evenings, where they could try out ideas. Reich eventually settled on an ensemble of six upright pianos in close proximity, which would allow very precise timing without being masked by the resonance of grand pianos.