Mr. Justice Raffles by E.W. Hornung

Raffles is a gentleman thief who supports himself by carrying out ingenious robberies through safecracking, lock-picking, masterful disguises, and unbelievable escapades. Well-dressed and well-spoken, Raffles is accompanied by his sidekick "Bunny" Manders; the two gentlemen cut a swathe of theft and adventure through the fashionable areas of London.