Jeff Regan, Investigator is a well-regarded example of the mid-century detective drama genre. The series features the eponymous protagonist, Jeff Regan, who works as a private investigator for the International Detective Bureau. The program's tone is characterized by the hard-boiled nature of Regan's character and his better relationship with the police as compared to his previous roles. The show's production involved the considerable talents of notable actors such as Jack Webb, Herb Butterfield, and Frank Nelson, as well as writers like E. Jack Neuman, Larry Roman, William Froug, and William Fifield.

The series was broadcast between July 10, 1948, and August 27, 1950, but was on hiatus for a year. Premiering on the CBS network, the first run ended on December 18, 1948, followed by the second run beginning on October 5, 1949. A total of several dozen episodes aired, including multiple incarnations of the series; Jack Webb initially helmed the show as the lead actor, followed by Frank Graham and Paul Dubov. Webb left the series after a pay dispute, moving on to star in Dragnet. The show ultimately ended after the tragic death of Frank Graham at the age of 35.

Sources: archive.org, wikipedia.org, otrcat.com