Progressive Jazz is a subgenre of jazz that emerged in the 1950s, characterized by its innovative approach to harmony, rhythm, and structure. Musicians began to experiment with complex time signatures and unconventional chord progressions, moving away from traditional jazz forms. This style often incorporates elements from other genres, such as classical music and avant-garde, creating a unique sound that challenges listeners. Key figures in Progressive Jazz include Miles Davis and John Coltrane, who pushed the boundaries of jazz with their groundbreaking compositions. This genre paved the way for future styles, influencing artists and shaping the evolution of modern jazz, making it a vital part of music history.