Robert William Chambers (May 26, 1865 – December 16, 1933) was an American artist and fiction writer, best known for his book of short stories titled The King in Yellow, published in 1895.

That kindly old investigator, Mr. Keen, Tracer of Lost Persons, sought missing and murdered individuals longer than any other fictional detective ever heard or seen on the air. For 18 years (1937-1955) Keen and his faithful assistant, Mike Clancy, entertained followers with their intuitive perception that kept listeners coming back for more. With 1690 nationwide broadcasts, Mr. Keen was the most resilient private detective in a namesake role. The nearest competitors were Nick Carter, Master Detective (726 broadcasts), The Adventures of Sherlock Holmes (657) and The Adventures of the Falcon (473). This book presents a portrait of both the beloved character and the venerable dramatic series. An introductory chapter examines the significance of the sleuth in American entertainment. A concerted effort is also made to properly define each Keen era and an appendix provides an episodic log of the program's 1690 broadcasts.

'The Tracer of Lost Persons' is a supernatural-mystery novel by Robert W. Chambers. It revolves around a man named Mr. Keen, who happens to be a specialist in finding missing people.

After helping Chip and Alex survive 15th-century London, Jonah and Katherine are summoned to help another missing child, Andrea, face her fate. Andrea is really Virginia Dare, from the Lost Colony of Roanoke. Jonah and Katherine are confident in their ability to help Andrea fix history, but when their journey goes dangerously awry, they realize that they may be in over their heads: They’ve landed in the wrong time period. Andrea doesn’t seem that interested in leaving the past. And even worse, it appears that someone has deliberately sabotaged their mission....

That "kindly old investigator," Mr. Keen, sought missing persons and unraveled crimes longer than any other fictional detective ever heard or seen on the air. For 18 years (1937-1955) and 1690 nationwide broadcasts, Keen and his faithful assistant Mike Clancy kept listeners coming back for more. The nearest competitor, Nick Carter, Master Detective, ran for 726 broadcasts. This definitive history recounts the actors and creators behind the series, the changes the show underwent, and the development of the Mr. Keen character. A complete episode guide details all of the program's 1,690 broadcasts.