Sir Arthur Conan Doyle 
The Sign of the Four (Diversion Classics) [EPUB ebook] 

Featuring an appendix of discussion questions, the Diversion Classics edition is ideal for use in book groups and classrooms.
When Mary Morstan approaches Sherlock Holmes and John Watson about the disappearance of her father, they are drawn into a mystery halfway across the world. As they investigate stolen treasure, escaped prisoners, and the East India Company, Holmes also contends with his drug habit. This classic addition to the detective genre is as thrilling and suspenseful today as it was two hundred years ago.