The Alice Factor — J. Robert Janes

As war looms over Europe, a diamond dealer fights the Nazis from behind enemy lines It is 1937, and the Antwerp Diamond Exchange is preparing for war. The Wehrmacht is hungry for industrial diamonds, without which it's impossible to manufacture armor, radios, or guns. For Richard Hagen, a rare gentile jewelry dealer, business has never been better. But this quiet diamond expert is about to begin a war of his own. On a business trip to Germany, Hagen attempts to sabotage Nazi efforts to secure the diamonds they need so desperately. Masquerading as a friend of the Reich, he sends home messages in a code based on Alice in Wonderland . The Antwerp Exchange is preparing to flee to London, but Hagen will remain in mainland Europe. As the Gestapo closes in, he will have to stay diamond-sharp to survive.