Presented here are four major theories behind the functioning of the world's presses: (1) the Authoritarian theory, which developed in the late Renaissance and was based on the idea that truth is the product of a few wise men; (2) the Libertarian theory, which arose from the works of men like Milton, Locke, Mill, and Jefferson and avowed that the search for truth is one of man's natural rights; (3) the Social Responsibility theory of the modern day: equal radio and television time for political candidates, the obligations of the newspaper in a one-paper town, etc. ; (4) the Soviet Communist theory, an expanded and more positive version of the old Authoritarian theory.