Rebecca Johnson has a fun article on Salon.com about what happened when her editor asked her to start gathering endorsement quotes for her novel.
It is a belief widely held that having quotes from authoritative famous people on your book cover will help convince the reader to buy it. "Regis Philbin loves this book, so I surely will, too!" people supposedly think. So in both fiction and nonfiction, authors are charged with enlisting the people with the right names and credentials to read their books and then say something nice about them.
Come to think of it, it's a huge imposition, and Rebecca met with all manner of opposition in her quest to find the "right" writers to blurb her. My favorite is the nameless writer approached at a party, who began edging away even before the question was asked. "The expression on her face--part horror, part sneer--was exactly what I would have expected had I released a large fart and asked what she thought of it," says Rebecca.
The process doesn't usually go smoothly for us here, either. One author sent brownies to Dr. Phil in an attempt to woo a quote out of him. She's still waiting, but I give her big points for her chutzpah. Most of our reviewers end up being smart people with impressive credentials, but of whom you've probably never heard.