Ian Ernest Gilmore Evans (né Green; May 13, 1912 – March 20, 1988) was a Canadian–American jazz pianist, arranger, composer and bandleader. He is widely recognized as one of the greatest orchestrators in jazz, playing an important role in the development of cool jazz, modal jazz, free jazz, and jazz fusion. He is best known for his acclaimed collaborations with Miles Davis.

Source: Wikipedia (https://en.wikipedia.org/wiki/Gil_Evans)