The vast majority of Henty's novels are historical. This one is a mystery. According to the introduction: ""Colonel Thorndyke's Secret" is a story so far out of the ordinary that it will not be inappropriate to speak a few words regarding the tale and its unusually successful author, Mr. George Alfred Henty. The plot of the story hinges upon the possession of a valuable bracelet, of diamonds, stolen from a Hindoo idol by a British soldier in India. This bracelet falls into the possession of Colonel Thorndyke, who, shortly afterward, is sent home to England because of his wounds. The secret concerning the bracelet is told to the Colonel's brother, a country squire, and the treasure is left to younger members of the Thorndyke family." According to Wikipedia: "George Alfred Henty (8 December 1832 - 16 November 1902), referred to as G. A. Henty, was a prolific English novelist, special correspondent, and Imperialist born in Trumpington, Cambridgeshire, England. He is best known for his historical adventure stories that were popular in the late 19th century. His works include Out on the Pampas (1871), The Young Buglers (1880), With Clive in India (1884) and Wulf the Saxon (1895)"