Hard bop is a style of jazz that emerged in the mid-1950s as a response to the cool jazz movement. It incorporates elements of rhythm and blues, gospel, and blues, emphasizing a strong, driving beat and expressive melodies. Musicians often use complex harmonies and improvisation, creating a more intense and emotional sound compared to earlier jazz styles. Key figures in hard bop include Art Blakey, Horace Silver, and Miles Davis. This genre often features a quintet format, typically with a saxophone, trumpet, piano, bass, and drums. Hard bop remains influential, shaping the development of later jazz styles and continuing to resonate with audiences today.