The good people at Random House have several videos showing the inner workings of a major publisher. Back in June they ran the following piece on cover design, one of the under-heralded arts in book publishing. A good cover can make a book; a bad one can kill it before it has a chance to get a foothold.
A book designer has a difficult job, one that requires he/she satisfy the author, their department supervisor, the sales and marketing teams, and their own artistic sensibilities. This video gives a glimpse behind the scenes of book covers.