England, 1935. Physicist Henry Barstow is on holiday when he meets the mysterious Simon Groom, a representative for an armaments manufacturer. Groom invites the professor to Ixania, a small nation-state in Eastern Europe whose growing weapons program threatens to destabilize the region. Only after suffering a blow to the head--which muddles his brain into believing he is Conway Carruthers, international spy--does the mild-mannered physicist agree to visit Ixania. But he quickly recognizes that Groom has a more sinister agenda, and Carruthers is the only man who can stop him.
"[Ambler] was wonderfully gifted. . . . It is a pleasure to see where the master began." --Chicago Tribune
"The thinking man's thriller writer." --The Washington Post
"Ambler is, quite simply, the best." --The New Yorker
"Busy and engaging. . . . [The Dark Frontier] is a romp, although with hints of the harder line that Ambler was to take in the later novels." --Los Angeles Times
"The foremost thriller writer of our time." --Time
"Mr. Ambler is a phenomenon!" --Alfred Hitchcock
"One of the masters of the thriller. . . . Ambler took the spy thriller out of the gentility of the drawing room and into the back streets . . . where it all really happened." --Associated Press
"Ambler is incapable of writing a dull paragraph."-- Sunday Times (London)