Zwickelbach & Co(1976)

Sean King and Michelle Maxwell aren't your typical pair of private investigators. As discredited Secret Service agents, their unique skills often give them a leg up on suspects and conventional law enforcement. He's charming and always one step ahead of the game; she's a fearless force to be reckoned with. As a team, they're unstoppable.

Barnaby Jones is a television detective series starring Buddy Ebsen and Lee Meriwether as father- and daughter-in-law who run a private detective firm in Los Angeles. The show ran on CBS from January 28, 1973 to April 3, 1980, beginning as a midseason replacement. William Conrad guest starred as Frank Cannon of Cannon on the first episode of Barnaby Jones, "Requiem for a Son" and the two series had a two-part crossover episode in 1975, "The Deadly Conspiracy".

Private detective Mike Hammer hunts down criminals on the mean streets of New York City.

Detective Mike Hammer uses his savvy grit against deceptive enemies in Southern California.

Glenn Hall runs a less-than-conventional detective. Her staff includes Roberta Young, a detective who goes to great lengths to get the job done; Manny Lott, the resident technology wiz; and Dana Plant, a former Santa Monica police detective.

Jonathan Ames, a young Brooklyn writer, is feeling lost. He's just gone through a painful break-up, thanks in part to his drinking, can't write his second novel, and carouses too much with his magazine editor. Rather than face reality, Jonathan turns instead to his fantasies — moonlighting as a private detective — because he wants to be a hero and a man of action.

Banacek is an American detective TV series starring George Peppard that aired on the NBC network from 1972 to 1974. The series was part of the rotating NBC Wednesday Mystery Movie anthology. It alternated in its time slot with several other shows but was the only one to last beyond its first season.

Jack Irish is a man getting his life back together again. A former criminal lawyer whose world imploded, he now spends his days as a part-time investigator, debt collector, apprentice cabinet maker, punter and sometime lover – the complete man really. An expert in finding those who don’t want to be found – dead or alive, Jack helps out his mates while avoiding the past. That is until the past finds him.

The View from Daniel Pike is a 1971–73 Scottish TV drama series created and written by Edward Boyd, and starring Roddy McMillan as Daniel Pike, a hard-boiled private detective based in Glasgow. A few of the stories were later adapted into book form.

Adrian Monk was once a rising star with the San Francisco Police Department, legendary for using unconventional means to solve the department's most baffling cases. But after the tragic (and still unsolved) murder of his wife Trudy, he developed an extreme case of obsessive-compulsive disorder. Now working as a private consultant, Monk continues to investigate cases in the most unconventional ways.

From England to Egypt, accompanied by his elegant and trustworthy sidekicks, the intelligent yet eccentrically-refined Belgian detective Hercule Poirot pits his wits against a collection of first class deceptions.

Sherlock Holmes uses his abilities to take on cases by private clients and those that the Scotland Yard are unable to solve, along with his friend Dr. Watson.

Brothers work as private investigators.

Mystery and suspense series based on Robert Parker's "Spenser" novels. Spenser, a private investigator living in Boston, gets involved in a new murder mystery each episode.

Tenspeed and Brown Shoe is an American detective/comedy series originally broadcast by the ABC network between January and June 1980. The series was created and executive produced by Stephen J. Cannell.

Randall and Hopkirk (Deceased) is a British private detective television series. In the initial episode Hopkirk is murdered during an investigation, but returns as a ghost. Randall is the only main character able to see or hear him, although certain minor characters are also able to do so in various circumstances throughout the series.

Stu Bailey and Jeff Spencer are the wisecracking, womanizing private-detective heroes of this Warner Brothers drama. They work out of an office located at 77 Sunset Strip in Los Angeles, California, right next door to a snazzy restaurant where Kookie works as a valet. The finger-snapping, slang-talking Kookie occasionally helps Stu and Jeff with their cases, and eventually becomes a full-fledged member of the detective agency. Rex Randolph and J.R. Hale also join the firm, and Suzanne is their leggy secretary.