• Spies of the Kaiser: Plotting the Downfall of England
• The Place of Dragons: A Mystery
• The Veiled Man
• The Mystery of the Green Ray
• The Great White Queen: A Tale of Treasure and Treason
• The Seven Secrets
• Whither Thou Goest
• The Count's Chauffeur
• Whatsoever a Man Soweth
• The Temptress
• Her Royal Highness: A Romance of the Chancelleries of Europe
• The Lost Million
• The Red Room
• The Mysterious Mr. Miller
• The Pauper of Park Lane
• The Great God Gold
• In White Raiment
• Devil's Dice
• An Eye for an Eye
• Hushed Up! A Mystery of London
• The Broken Thread
• The House of Whispers
• If Sinners Entice Thee
• As We Forgive Them
• Behind the Throne
• Guilty Bonds
• The Mysterious Three
• The Wiles of the Wicked
• The Bond of Black
• The Sign of the Stranger
• The Bomb-Makers
• The Four Faces: A Mystery
• The Hunchback of Westminster
• Mademoiselle of Monte Carlo
• The Stolen Statesman: Being the Story of a Hushed Up Mystery