The popular demand for Tom Clancy's action novels exceeded his ability to write new books. As a result, his publisher hired ghostwriters to write novels in the Clancy style.
A ghostwriter is hired to write literary or journalistic works, speeches, or other texts that are officially credited to another person as the author. Celebrities, executives, participants in timely news stories, and political leaders often hire ghostwriters to draft or edit autobiographies, memoirs, magazine articles, or other written material. In music, ghostwriters are often used to write songs, lyrics, and instrumental pieces. Screenplay authors can also use ghostwriters to either edit or rewrite their scripts to improve them.
Usually, there is a confidentiality clause in the contract between the ghostwriter and the credited author that obligates the former to remain anonymous. Sometimes the ghostwriter is acknowledged by the author or publisher for his or her writing services, euphemistically called a "researcher" or "research assistant", but often the ghostwriter is not credited.
Ghostwriting (or simply "ghosting") also occurs in other creative fields. Composers have long hired ghostwriters to help them to write musical pieces and songs; Wolfgang Amadeus Mozart is an example of a well-known composer who was paid to ghostwrite music for wealthy patrons. Ghosting also occurs in popular music. A pop music ghostwriter writes lyrics and a melody in the style of the credited musician. In hip hop music, the increasing use of ghostwriters by high-profile hip-hop stars has led to controversy. In the visual arts, it is not uncommon in either fine art or commercial art such as comics for a number of assistants to do work on a piece that is credited to a single artist. However, when credit is established for the writer, the acknowledgement of their contribution is public domain and the writer in question would not be considered a ghostwriter.
A consultant or career-switcher may pay a ghostwriter to write a book on a topic in their professional area, to establish or enhance credibility as an 'expert' in their field. Public officials and politicians employ "correspondence officers" to respond to the large volume of official correspondence. A number of papal encyclicals have been written by ghostwriters. A controversial and scientifically unethical practice is medical ghostwriting, where biotech or pharmaceutical companies pay professional writers to produce papers and then recruit (via a payment or as a perk) other scientists or physicians to attach their names to these articles before they are published in medical or scientific journals. Some university and college students hire ghostwriters from essay mills to write entrance essays, term papers, theses, and dissertations. This is largely considered unethical unless the actual ghostwriting work is just light editing.
Ghostwriters are hired for numerous reasons. In many cases, celebrities or public figures do not have the time, discipline, or writing skills to write and research a several-hundred page autobiography or "how-to" book. Even if a celebrity or public figure has the writing skills to pen a short article, they may not know how to structure and edit a several-hundred page book so that it is captivating and well-paced. In other cases, publishers use ghostwriters to increase the number of books that can be published each year under the name of well-known, highly marketable authors, or to quickly release a topical book that ties in with a recent or upcoming newsworthy event.