The literary equivalent of the
fat old guys who sang on the Milli Vanilli records. In other words, a writer who writes under someone else's
name with their consent. The so-called author gets his or her
name printed on the cover and receives credit for the writing while the ghostwriter does the actual work.
Celebrity and politician autobiographies are usually ghostwritten, due to the "author" having no writing
talent whatsoever. What, you think Jenna Jameson and Hillary Clinton actually wrote their books?
Ghostwriters are also disturbingly
common in fiction, not that anyone gives a rat's ass that Tom Clancy doesn't actually write his crappy novels.