“Bebop” appeared in the 1940s. It introduced more complex melodies, harmonies, and rhythms, as well as more expressive drumming. In the late '40s, Miles Davis ushered in “cool jazz”' s smoother, more harmonic sound. The last of the classic jazz styles, “hard bop,” was more soulful, and sometimes borrowed from R&B and gospel themes. Later strains of jazz include “fusion,” “bossa nova,” and “funk.”