John Buchan 
Mr. Standfast [EPUB ebook] 

In this nail-biting adventure story, Hannay must outwit a foe far more intelligent than himself; muster the courage to propose to the lovely, clever Mary Lamington; and survive a brutal war. Although Mr. Standfast is a sequel to The Thirty-Nine Steps, it offers far more characterisation and philosophy than the earlier book. For its pace and suspense, its changes of scenery and thrilling descriptions of the last great battles against the Germans, Mr Standfast offers everything that has made its author so enduringly popular.