Minimalism, in music, is a movement from the 20th century. Most popular in 1960s America, it involves using little or limited 'raw' materials (e.g. in music this included minimal pitch and harmony). Notable minimalist composers include Steve Reich, Phillip Glass and Terry Riley. To recognize minimalism in music, listen for features such as little pitch range and variation, repetitive ostinatos, little or no functional harmony (and slow harmonic rhythms), and complicated rhythmic and metric systems.