James Spencer Mills III (May 20, 1932 – December 4, 2011) was an American novelist, screenwriter and journalist.
Mills wrote two New York Times bestsellers, Report to the Commissioner, a novel, and The Underground Empire, a study of international narcotics trafficking. His books The Panic in Needle Park and Report to the Commissioner were later made into major motion pictures by 20th Century Fox and United Artists respectively. The credibility of The Underground Empire was challenged in a lengthy front-page article in the Los Angeles Times.