A ghostwriter is a professional writer whose published work is credited to another person. One famous ghostwriter is Andrew Neiderman. He was hired by the estate of V. C. Andrews, who died in 1986. Niederman completed the "Casteel" series of books and continues writing books credited to Andrews.
Ghostwriters are paid a fee to help write the autobiographies of celebrities, athletes and politicians. They also help write letters, song lyrics, magazine and news articles that get published under someone else's name.