This site created by CogniText. Professional publicists have access to tools that many artists and writers simply do not have, particularly membership in national wire services. These are used to send out information about clients' work to news editors, TV and radio producers, librarians and other volume purchasers, specialty markets, and book and art reviewers at high circulation magazines. Some of these services reach over 2000 major producers.
Maximum exposure is the goal.
In addition to wire services, publicists will often have acquaintances, gleaned from years of meeting people in connection with previous clients, that a writer or artist, once again, simply does not have. However, the bottom line is that they do sell books. And yes, hiring a publicist will improve one's chances of getting on Oprah. In your opening sentence explain why you are writing. Describe your book concisely.