Top 40 is a listing of the 40 most popular single records in the nation for a given week, and is derived from radio station playlists and retail sales. The listing is based on trade magazines including Gavin Report, Cashbox, and Billboard. Top 40 also is an AM radio format that consists of music, trivial talk, news, and promotions including services, money, and goods given to listeners. Though Top 40 radio has undergone many changes in its 45-year history, it remains a viable format. From 1956 to the present, Top 40 has provided Americans, especially those born in the 1940s, a musical smorgasbord served up through their favorite disc jockey. Disc jockeys were chosen on the basis of their voice, excitement, and sex appeal. The Top 40 format did not leave much room for personalities, and for that reason did not appeal to some disc jockeys. At first, Top 40 was not aimed at a teenage...