John Buchan 
Greenmantle 

Joined by Peter Pienaar, the old Boer Scout; John S. Blenkiron, the American determined to fight the Kaiser; and Sandy Arbuthnot, adventurer Richard Hannay travel across war-torn Europe in search of the grotesque Stumm and the evil beauty of Hilda von Einem. This espionage novel set during the First World War features thrilling disguises, despicable plots, and some of the most devious spies in literature.