Edgar Wallace 
The Black 

Fashionable Londoner James Morlake is a gentleman with many secrets and several particularly valuable skills – like terrorizing bankers across the city. His Moorish servant Mahmet has some secrets to hide as well, particularly when his employer gives him the odd task to perform in the dead of night in dark London. A collection of short stories from Edgar Wallace featuring a private detective who tracks down blackmailers. When you do reach the end you will anxiously await a follow on. „Black” grabs you immediately, then takes you on a high speed international trip at race pace.