The mass media as interdependent parts of a larger social system both control and are controlled by other subsystems. The various combinations of control, in turn, determine the functions the media system will serve. In the 1960's, the Cuban mass media underwent frequent change that reflected the volatility of the revolutionary process. Today, although all mass communication operates under Marxist-Leninist principles, Cuban media are organized in varying fashions. In broadcasting, the organization is highly centralized, while in the other media, it is relatively decentralized. Under this diverse organizational structure, the controls exercised by the revolutionary elite, such as formal censorship and the more frequent cooptation, are the most powerful and obvious in the process, but there are increasing indications that other subsystems, most notably the mass audience, are also exercising control over media content. After the economic disaster of 1970, Cuban President Castro reorganized his government to include a larger and more diverse power structure and more mass participation in public decision making. Reflecting these changes in society, the mass media are now serving an expanded role of feedback control as well as the traditional distribution control. Public criticism of the tactical operations of the government is transmitted vertically, and advocacy of the needs of major sectors of the power structure is carried horizontally by the mass media to the political elite. That allows broadly based sectors of Cuban society to discuss certain issues among themselves and with the leadership without disrupting the progress of the revolution. (HOD)