Béla Bartók
Bartók’s music has many modern techniques such atonality, bitonality and modern harmonies. He often uses different kinds of scales (not just major and minor ones), and very complicated rhythms. A lot of these are inspired by the folk music he heard. He wrote a lot of piano music, including some easy pieces for people who are learning the piano. This includes a collection of pieces in six volumes called Mikrokosmos which are very popular with young musicians today.