Communication is the key to Public Relations communicating the right message to the public, employees, shareholders and other specific target audiences.
Public Relations is :

Projecting the right message
Cost effective
An excellent management tool
A squirrel is just a rat with good Public Relations!
Public Relations (PR) is an often misunderstood and undervalued management tool. To many it is seen as just another form of advertising while others dismiss PR as dealing with journalists and sending out press releases.In fact, it can play a central role in the achievements of specific objectives at all levels of an organisations work, by focusing, reinforcing and communicating an effective message.
Used properly, Public Relations is an excellent and cost effective method of improving, the image of an individual, organisation or product. It is about ensuring that your audience receives and accepts, the message you wish to project. Public relations involves many other disciplines and it can have an impact on every aspect of an organisation. It is about projecting the right message and as such, it can involve press relations, advertising, marketing, sponsorship, exhibitions, local community events, the environment and public affairs.