Art rock is a term used to describe a subgenre of rock music with "experimental or avant-garde influences" that emphasizes "novel sonic texture." Art rock is an "intrinsically album-based" form, which takes "advantage of the format's capacity for longer, more complex compositions and extended instrumental explorations. The Golden Age of Rock lectures define art rock as "a piece of music in the rock idiom that is appealing more intellectually or musically, that is, not formulated along pop lines for mass consumption. It's usually somewhat experimental. It often employs a long structure with several themes like classical music, though sometimes it's a suite of individual songs. One unifying feature is that Art Rock almost always features keyboards more than guitar." As well, art rock is "not so much for dancing as for listening and it often tells a story or has a philosophical theme to the lyrics."