Where Is the Mainstream of Music in the Late Twentieth Century?

The author explores the mainstream of music in the United States as of the late twentieth century, and sees a shift of the mainstream away from more serious music toward popular music. That is, much of earlier American popular music has been transported to the fringes of the mainstream and much of what used to be on the mainstream fringe has been absorbed by the mainstream. The implications of this cultural metamorphosis for music libraries is examined.