""The Mystery Of The Five Hundred Diamonds"" is a thrilling mystery novel written by Robert Barr. The story begins when a wealthy businessman named Mr. Charles Vandrift hires a group of diamond merchants to transport five hundred diamonds from South Africa to England. However, the diamonds go missing during the journey, and Vandrift suspects foul play. To solve the mystery, Vandrift hires a detective named Monsieur Eugene Valmont, who is known for...