The Adventure of the Engineer's Thumb (Unabridged‪)‬

This is a story from the The Adventures of Sherlock Holmes II collection.

In this collection are four of the finest cases of Mr. Sherlock Holmes, narrated by his faithful friend and admirer Dr. Watson. What was the mystery of the engineer's thumb? What was behind the disappearance of the race horse? Why did masked royalty walk up to see Holmes in Baker Street? These and other puzzles are solved in this collection by this bloodhound of a genius.