Progressive rock, sometimes shortened to prog rock or prog, is a form of rock music that evolved in the late 1960s and early 1970s, principally from psychedelic rock, and ultimately as a result of experimentation with electronic keyboard instruments, jazz-rock fusion, blues, and mainly classical music.
Progressive rock compositions are more elaborate than the standard rock or popular verse-chorus based song structures. As well, the arrangements often incorporate elements drawn from classical, jazz, world music, avant-garde music, hard rock, and heavy metal. Songs with lyrics, are often conceptual, philosophical, or based in fantasy.
Progressive rock reached the peak of its popularity in the 1970s and has continued as a form of popular music to this day. The term was applied to the music of bands such as King Crimson, Yes, Pink Floyd and Emerson, Lake and Palmer (ELP). Other notable progressive rock bands include Jethro Tull, Genesis, Gentle Giant, The Nice, Kansas, and Rush.