摘要
the importance of copyleft for the present society is established. a critical analysis of copyright is made, and its antecedents and definition are exposed. the principles of free software, as the basis for the bazaar model for the creation of computer programs are dealt with. the values promoted by the copyleft are enunciated. the licenses existing in the technological and cultural world, which are developed starting from the copyleft, are described and analyzed. the case of cuba is exposed as a particularity. a classification, according to the author and the content of the work is recommended to facilitate the licensing of a creation. the copyleft is related to knowledge management and it is explained how this working philosophy is connected with the commercial world.