Gaston Leroux 
The Secret Of The Night 

The mystery books The Secret of the Night, also known as Rouletabille and the Tsar, was written by French author Gaston Leroux in 1913. The Mystery of the Yellow Room and The Perfume of the Lady in Black came before it in his trilogy of books involving the fictitious investigator Joseph Rouletabille. The plot of The Secret Of The Night starts with Nicholas II of Russia who hires Joseph Rouletabille in 1905 to keep an eye on one of his generals whose life has been threatened by revolutionaries. It is one of the best mystery novels written by Gaston Leroux. Readers will be thrilled once they the mystery unfolds.