Public relations (or "PR") is one of the most commonly misused terms there is. If a
public figure makes a
faux pas, this is often referred to as a public relations mistake. This is not correct as an individual is not an organization, and therefore public relations is irrelevant to him/her.
Public relations is managed communication between an organization and its publics. There is no such thing as "the general public." Every organization has a set of distinct publics, distinguished by their different interests. Self interest is the driving force behind public relations. A good PR agent is constantly thinking of how he or she can appeal to his or her publics' self interests. Public relations is also a receiver phenomenon. True communication only occurs when a message is received and interpreted as its creator intended.
Public relations is also known as corporate communications within many organizations. One does not have to be licensed or even have any sort of credentials to practice PR. Anyone can write a press release and call oneself a public relations practitioner. Whether this person will be successful or not is another story. It is not likely that public relations will ever be a licensed field, as United States law states that a field cannot introduce a licensing requirement for the purpose of keeping some people (i.e. hacks) out of their field. Accreditation is available on a voluntary basis. One can be accredited by passing a test, whether they have a degree or not.
The most significant society for those dealing in public relations is the Public Relations Society of America (PRSA).