Public Opinion is a 1922 book on media and democracy by Walter Lippmann. Among other things, it argues that twentieth century advances in the technology of "the manufacture of consent" amount to "a revolution" in "the practice of democracy" because this allows the control over public opinion about the world and about the public's interests in that world. Control of public opinion is a means to controlling public behavior.Fact: date=February 2007

The book is divided into several parts:

1. Part 1: The World Outside and Pictures in Our Heads: Discussess the inability of man to avoid fiction as he can't always experience reality. Stress is laid on the interpretation of reality differently by each person.
2. The self-centered man: The preconceived notions of man about the pseudo-realities and more likely to have opinions about the events that matter him. Man is more likely to articulate opinion which brings him personal gain. Large part of the crowd is "bewildered herd' and they form opinions which require the backing of the nobility. If the opinion is pro elite then its accepted but if it is otherwise then the consent has to be "manufactured" and this happens through mainstream media.
3. The buying public: The bewildered herd has to pay for understanding the unseen environment through the media. The irony being the people's opinion is important yet they have to pay for it to be accepted. Hence people will be choosy and will buy the most factual media at the lowest price. Lippmann quoted "For a dollar you may not even get an armful of candy but for a dollar or less people expect reality/representations of truth to fall into their laps." Hence the duality of media appears i.e. besides their social function their role of surviving in the market in profits.
4. Nature of news: People put out news that is already confirmed and there is less dispute over it. Officially available issues will make news and the non official ones will be less available or easily used for propaganda.
5. News truth and conclusion: The function of news is to signal an event and this signaling eventually is a consequence of selection and judgment. Thus journalism is able to create and thus sow the seeds of opinion.

When properly utilized, the manufacture of consent, Lippmann argues, is useful and necessary for modern society because "the common interests"—the general concerns of all people—are not obvious in many cases and only become clear upon careful data collection and analysis, which most of the people are either uninterested in or incapable of doing. Most people, therefore, must have the world summarized for them by those who are well-informed.

Since Lippmann includes much of the political elite within the set of those incapable of properly understanding by themselves the complex "unseen environment" in which the affairs of the modern state take place, he proposes having professionals (a "specialized class") collect and analyze data and present the conclusions to the decision makers. The decision makers then take decisions and use the "art of persuasion" to inform the public about the decisions and the circumstances surrounding them.