Cannon was a detective series which ran on CBS from 1971 to 1976. It starred William Conrad as the overweight detective Frank Cannon, who charged high fees to his well-to-do clients so that he could work for poorer clients at little or no charge. He also used it to indulge his high-priced lifestyle, which included maintenance on his Lincoln Mark IV, which was frequently wrecked. Cannon had once been a police officer, but was discharged from the force for being overweight. He was also once married with a son, but both his wife and his son were murdered—Cannon, in a tearfully angry confrontation, tracked down the man responsible.

The series was a Quinn Martin production, and featured many of the company's well-known stylistic quirks. Cannon marked the first time a QM series aired on a network other than ABC.

Frank Cannon frequently crossed over to appear on Barnaby Jones, another QM series which ran concurrently with Cannon on CBS between January 1973 and the latter's cancellation.

The weekly adventures of Frank Cannon, an overweight, balding ex-cop with a deep voice and expensive tastes in culinary pleasures, who becomes a high-priced private investigator. Since Cannon's girth didn't allow for many fist-fights and gun battles (although there were many), the series substituted car chases and high production values in their place. Written by Marty McKee

Most clients paid dearly for the services of Detective Cannon. The high fee underwrote his expensive lifestyle. Fine food left him too overweight to fight anybody, so he mostly drove around Los Angeles in his Continental. Written by Ed Stephan