Philip K. Dick's 1962 novel 'The Man in the High Castle' postulates an alternate history in which World War II is won by the Axis powers of Germany and Japan. As with most novels like this, the fantasy is only fantastic in that it is an extreme version of what is visible in the non-alternate world. In that sense, the premise isn't as 'alternate' as the author may have us believe.
While the novel is amusing, it isn't a particularly well-written book. It shares in the failure of many such dystopian novels (Handmade's Tale is very similar) to provide a truly forward moving narrative. Once the author has exhausted their turn at defining this scary world, it is more or less over. We are left to figure out for ourselves where to take the story from there. Not that there is anything wrong with that per se, it is just that if that were really up to us then why write a novel and not just short-story where you just postulate the theory and be done with it?
The theme, though I am not sure if stated quite that way, is powerful. Hitler and Nazism may have lost the proverbial battle but if the passage of time has taught us anything, it is clear that his regressive ideas really did win the larger war.