With very few sudden, radical changes — just a handful of constant elements smoothly, gradually building and developing — the way that Steve Reich's musical language has come together, over his decades-long career, actually resembles the structure of his own music.
His earliest acknowledged works, so austerely composed that they resemble conceptual art as much as classical music, contain the seeds of nearly his entire oeuvre: repeated chords or melodies slowly stretched out into long drones (in pieces like Four Organs, 1970); staccato rhythms that drift out of phase (e.g., Piano Phase, 1967); recorded speech used as melodic material (Come Out, 1966).
Like his contemporary and admirer Philip Glass, Reich originally composed his music for his own, highly specialized ensemble, arguably culminating in the lengthy Music for 18 Musicians (1974-1976). But, like Glass, as his reputation grew at the end of the 70s, he began to accept commissions to write for established ensembles. Reich is now hesitant to embrace his own music for the massed forces of the symphony orchestra, especially the Variations for Winds, Strings and Keyboards (1979) — which is nevertheless a highly polished and even affecting work — preferring the clean, spare sound of a chamber ensemble.
Reich's music is highly cerebral and unsentimental, but it hardly exists in a spiritual vacuum — Come Out was written as a protest piece, sampling the voice of a victim of police brutality. Much of Reich's work deals with his Jewish identity, as in Tehillim (1981), his Hebrew setting from the Book of Psalms, or Different Trains (1988), an exceedingly austere Holocaust memorial using snippets of recorded conversation with survivors as the basis for an accompaniment by the Kronos Quartet.
He extended his documentary style to a pair of full-length video operas created with his wife. The Cave (1993) and Three Tales (1998-2002) set to music snippets from original interviews regarding, respectively, the biblical Abraham, and the potentially disastrous physical or spiritual consequences of new technologies. 1994's City Life is a more upbeat look at the bustle of New York City living, though it ends on a darker note with FDNY radio samples from the 1993 World Trade Center bombings.
Another new area for Reich is his music for multiple ensembles, starting with his 1998 Triple Quartet for three string quartets (premiered by the Kronos Quartet with tape accompaniment), finally recognized by the Pulitzer Prize in 2009 for his 2008 Double Sextet (for eighth blackbird and tape), and followed by 2x5 for two rock bands (2008), building dense and often dissonant textures from these rich resources.
More recently, Reich has returned again to documentary music with the piece WTC 9/11, a musical 2011 memorial commissioned by the Kronos Quartet to commemorate the victims of the second terror attack on the World Trade Center, sampling the watch kept at the disaster site for Jewish victims of the catastrophe and closing the circle beginning with City Life.