Steve Reich been around for a long time, and in the time, he's released a lot of material. As a composer, he helped lay the foundation for minimalist music...taking short loops and slowly modifying and altering the way the sound as they repeat over and over, creating longer pieces composed of just a few bars of actual music stitched together, layered over each other, and subtly manipulated. By using this seemingly simple technique, he's created varied compositions that range from highly intense and emotionally charged to more subdued and calming. The two samples below show the stylistic diversity just mentioned, "Third Movement Part One" from "The Desert Music" has a more traditional classical music style while "Different Trains: America - Before the War" from "Different Trains + Electric Counterpoint" has an energy that drives the composition forward and creates a wonderful sense of tension.
Steve Reich - Third Movement Part One (from "The Desert Music")
Steve Reich - Different Trains: America - Before the War (from "Different Trains + Electric Counterpoint")