Beadle’s Dime Novels series description
Original publisher’s blurb: “Who has not heard of ‘Old King Brady,’ the celebrated detective, who has unraveled more mysteries than any sleuth ever heard of? In the stories to be published in SECRET SERVICE, he will be assisted by a young man known as ‘Young King Brady,’ whose only aim in life is to exceed ‘Old King Brady’ in working up dangerous cases and running the criminals to earth. How well he does so will be fully explained in the following stories published in SECRET SERVICE.”
One of the most popular and profitable of the first color-covered nickel weeklies, the “Secret Service” series featuring “Old and Young King Brady, Detectives,” started January 27, 1899, and came out like clockwork every Friday for more than two and a half decades, by which time more than thirteen hundred issues had been published. Frank Tousey of New York, the publisher, used an already-popular character—Old King Brady—invented decades earlier by one of the better writers on his staff, Francis Worcester Doughty. Since the anonymously-credited author on every Secret Service issue is “A New York Detective,” there is no way to know for sure which of the Secret Service stories—if any—were written by Mr. Doughty and which were written by other writers... and for all we know every story was a group effort that happened over beers at the nearest tavern. But according to the Edward T. LeBlanc Memorial Dime Novel Bibliography, “Doughty’s stories can be identified by the ending. He always ended his stories with the exact title of the story.”