Harold A. Innis 
Empire and Communications [PDF ebook] 

It’s been said that without Harold A. Innis there could have been no Marshall Mc Luhan. Empire and Communications is one of Innis’s most important contributions to the debate about how media influence the development of consciousness and societies. In this seminal text, he traces humanity’s movement from the oral tradition of preliterate cultures to the electronic media of recent times. Along the way, he presents his own influential concepts of oral communication, time and space bias, and monopolies of knowledge.