Cases from the practice of the greatest detective of all times, which were only mentioned in his stories by his friend and assistant Dr. Watson. Why was Holmes so interested in the “case of the missing cousin”? What was the mystery of “Colonel Warburton’s madness”? What did he imagine? is the mysterious “nightmare of Deptford”? And more, more - the unknown cases of Sherlock Holmes! The most unusual crimes and the most mysterious investigations that Sir Arthur Conan Doyle himself intended, but did not have time to tell, and which were completed by his son Adrian Conan Doyle and the famous master of the classical detective John Dixon Carr.