William Bayer is an American novelist, the author of Switch, among other works.
Bayer has written a series of novels featuring fictional New York Police Department lieutenant Frank Janek. He has also written adaptions of his novels for television, and written for other TV shows. Switch was the source for seven television movies, including two four-hour mini-series. In all of them the main character, NYPD Detective Frank Janek, was played by the actor Richard Crenna. All seven movies were broadcast nationally by CBS in prime time.
Bayer's books have been translated into French, Italian, German, Dutch, Japanese and nine other foreign languages. He has written two novels under the pseudonym David Hunt, later republished in ebook editions under his own name. He wrote and directed the 1971 feature film Mississippi Summer which run the Best First Feature Award at the 1970 Chicago International Film Festival.