The British post-punk legends Gang of Four have influenced indie music from Run the Jewels to R.E.M. Now they are giving fans a special gift: a giant box set, "77-81", comprised of a live 2xLP and a cassette of demos. On the demo cassettes: one side is a compilation of three different late-1970s recordings, the other from a 1981 session at Abbey Road Studios. Jon King, a founder of the group, walks through the box set and tells stories of the gigs and recordings over the years.