Everything you need to understand or teach The Salzburg Connection by Helen Maclnnes.
MacInnes has one principle theme: Liberty is always in danger. In this novel, Nazis wish to destabilize Western governments in order to ultimately regain power. They will stop at nothing to carry out their goals; the individual means nothing to them. They will murder, or commit any other crime, to achieve their goals because they believe fanatically in the destruction of individual liberties and the desirability of an "orderly" world under their control.
Another thread animating this novel is the possibility and the desirability of romantic love. One's true love may be difficult to identify at first; he or she may seem rather innocuous, while the person one thinks he or she loves may prove to be an enemy agent. However, all difficulties are resolved by the end of the novel and the reader is assured that the hero and heroine, despite the dangers they suffer, will marry...