Miles Davis, 1970. Fusion's founding text — electric, free, dense.
From Wikipedia
Bitches Brew is a studio album by the American jazz trumpeter, composer, and bandleader Miles Davis. It was recorded from August 19 to 21, 1969, at Columbia's Studio B in New York City and released on March 30, 1970, by Columbia Records. It marked Davis's continuing experimentation with electric instruments that he had featured on his previous record, the critically acclaimed In a Silent Way (1969). With these instruments, such as the electric piano and guitar, Davis departed from traditional jazz rhythms in favor of loose, rock-influenced arrangements based on improvisation. The final tracks were edited and pieced together by producer Teo Macero.