In 1893, young army officer Cecil Hambrough was murdered at the sprawling Ardlamont estate in Scotland, unleashing one of the most gripping court cases Victorian Britain had ever known. Even more remarkably, the case brought together two pioneering forensic experts - Joseph Bell and Henry Littlejohn - two men upon whom Arthur Conan Doyle's Sherlock Holmes happened to be based. It is their involvement in the Ardlamont affair that reveals how the world's most famous detective came to be: the worlds of crime fiction and crime fact were about to collide spectacularly.

In this extraordinary book, Daniel Smith outlines the key roles of the two men whose powers of deduction had so inspired Doyle and explores the real-world origins of Sherlock Holmes through the prism of a mystery as engrossing as any case the Great Detective ever tackled.