Cannon is a detective series which ran on CBS from 1971 to 1976. 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.Cannon stars William Conrad as the overweight detective Frank Cannon, who had resigned from the LAPD and become a private detective. He 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 Continental Mark IV, which was frequently wrecked.
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 Barnaby Jones character, played by Buddy Ebsen, was introduced in the third-season episode "Requiem for a Son" in 1973. The two-part episode "The Deadly Conspiracy" (1975) began on Cannon and concluded on Barnaby Jones.