William Le Queux 
Sant of the Secret Service: Some Revelations of Spies and Spying [EPUB ebook] 

Originally published in 1918 as "Sant of the Secret Service, " this novel describes the ongoing adventures of Gerry Sant—spy for the allied forces during the First World War. He’s "cheerful, optimistic and modest;" he often telephones for the assistance of Gabrielle Soyez, female agent of the British Secret Service, to carry out surveillance and sometimes to infiltrate the enemy in disguise. The author, William Le Queux, was one of the first creators of the spy story. A journalist-turned-author, he successfully combined his passionate interest in national security and new technological developments with his detailed knowledge of travel and high society in Europe, in these and other collections of short stories of intrigue and espionage. These are well-written, thrilling adventures. A must-have for classic spy fiction fans! (Amazon)