If you can influence the leaders, either with or without their conscious cooperation, you automatically influence the group which they sway. But men … - Edward Bernays

The new profession of public relations has grown up because of the increasing complexity of modern life and the consequent necessity for making the actions of one part of the public understandable to other sectors of the public. It is due, too, to the increasing dependence of organized power of all sorts upon public opinion. Governments, whether they are monarchical, constitutional, democratic or communist, depend upon acquiescent public opinion for the success of their efforts and, in fact, government is government only by virtue of public acquiescence. Industries, public utilities, educational movements, indeed all groups representing any concept or product, whether they are majority or minority ideas, succeed only because of approving public opinion. Public opinion is the unacknowledged partner in all broad efforts. The public relations counsel, then, is the agent who, working with modern media of communications and the group formations of society, brings an idea to the consciousness of the public.

It is chiefly the psychologists of the school of Freud who have pointed out that many of man's thoughts and actions are compensatory substitutes for desires which he has been obliged to suppress. A thing may be desired not for its intrinsic worth or usefulness, but because he has unconsciously come to see in it a symbol of something else, the desire for which he is ashamed to admit to himself...This general principle, that men are very largely actuated by motives which they conceal from themselves, is as true of mass as of individual psychology...Human desires are the steam which makes the soial machine work. Only by understanding them can the propagandist control that cast, loose-jointed mechanism which is modern society.

The best place to find things: the public library.