Information dissemination is more than a matter of gathering facts and putting words together because writers must work within the opportunities and limits provided by the technology, societal values, the communications process, economic constraints of the media business, and the needs of the audience. This chapter explores the theoretical context in which print, broadcast, and internet journalists, and public relations professionals write and seek to communicate. Theories discussed include: individual differences; social categories; social influence; selective attention, perception, retention, and recall; stereotypes; wants and needs gratification theory; two-step and multi-step flow of communication; acculturation; agenda setting; framing; and social responsibility. What the media most commonly do is reinforce opinions, attitudes and beliefs, and maintain the status quo, although some attitude modification is possible. For the most part audiences reject or ignore messages that run counter to already-held opinions, attitudes, and beliefs, a reminder to the novice media writer that communication is not simple and carries no guarantee of success.