Threat of Hitler's Rise Motif
The novel was written before the outbreak of World War II, but Hitler's rise to power was still something that the rest of the world were aware of and deeply concerned about. The reference to burning books that did not agree with everything that Hitler said shows a concern for democracy that the author can already see is deeply threatened by his rise to power. The book continues to warn against what a world would look like with Hitler at the helm and also references his own view of himself as godlike.
Kristalnacht Allegory
The episode where books that did not agree with Hitler's philosophies were burned is allegorical of the real life book burnings that occurred at the beginning of the Nazi regime. Although a very small number of copies of pre-Hitler literature existed they were considered to be contraband and illegal publications. The Nazis burned any book that did not espouse the same thing that was espoused by their leader.
Underground Opposition Allegory
As in all dictatorships and tyrannies, the Nazi world of the novel has a thriving "underground", comprising of people like Alfred who do not drink the Hitler Kool-Aid, and are wholeheartedly opposed to everything that he is doing. This is allegorical of the real German underground resistance, that continued to keep copies of illicit pre-reich materials and tried to make sure that news of what Hitler was doing was leaked to those overseas who might be able to do something about it.
Knights Symbol
The Knights who preached the word of Hitler are a symbol of the belief that Nazism was in some ways linked to or derived from the occult. There are schools of thought that contend Hitler was an occultist, and that many of the Nazi symbols bore a startling resemblance to those found in occult or satanist practice. The Knights are described similarly to occult figures who were more like priests than they were military knights or protectors, a symbol of the suspicion that Hitler was engaged in occultism.
Hitler's Pre-War Appearance
When Alfred sees the book that shows a photograph of Hitler before the war he realizes that far from being a god-like figure, he was a little man with a fat belly and dark hair. This is a symbol to him of Hitler's fraudulence and the fact that he is passing himself of as a god when he is clearly a man.
