What are the central themes in Graham Greene's "Our Man in Havana?"

Our Man in Havana, a satirical send-up of spy novels, is primarily concerned with loyalty and hypocrisy. Cold War intrigue is the central theme that holds the novel together, as a British man living in Cuba is recruited to conduct espionage—a position for which he is entirely unqualified. James Wormold wants to serve his country, but he is not fully convinced that the investigations he is asked to conduct are warranted. Initially, he does not take his commitment seriously but instead fabricates disinformation to feed to his superiors. His perspective changes when one of his friends is killed and he must consider his own complicity in causing his death.
While James does step into the role he has been impersonating and thwarts some evil-doers, he also learns the extent of the hypocrisy of his superiors who not only sweep things under the rug but extravagantly reward him to keep him quiet.