C81 was a cassette compiled for the British magazine New Musical Express in 1981 (hence (C)assette 81) and released in conjunction with the record label Rough Trade. Featuring a number of contemporary musical acts and performers, it was intended to mark the first 5 years of the independent label movement in the UK record industry and Rough Trade itself. It was the first in a series of many cassette releases from the paper, including the C86 compilation of 1986.
The tape contained a set of 25 diverse tracks ranging from post-punk (Red Crayola, Essential Logic, D.A.F., The Raincoats), jazz (James Blood Ulmer), poetry (John Cooper Clarke), ska (The Beat), electronic (Cabaret Voltaire) to veteran 'Canterbury Scene' performer Robert Wyatt. It was accompanied by the 'C81 Owner's Manual', a 32-page booklet of lyrics and artwork that readers would assemble themselves by cutting up and folding a page from the tabloid sized magazine. This consisted of 16 small double sided panels, and was designed to be slipped into the cassette case. A running joke throughout the booklet was the comparison of a number of acts on the tape to various periods in the history of the Velvet Underground.