From wiki

The Iron Dream is a metafictional 1972 alternate history novel by American author Norman Spinrad. The book has a nested narrative that tells a story within a story. On the surface, the novel presents a post-apocalyptic adventure tale entitled Lord of the Swastika, written by an alternate-history Adolf Hitler shortly before his death in 1953. In this timeline, Hitler emigrated from Germany to the United States in 1919 after the Great War, and used his modest artistic skills to become first a pulp science fiction illustrator and later a successful writer, telling lurid, purple-prosed, pro-fascism stories under a thin science fiction veneer. The nested narrative is followed by a faux scholarly analysis by a fictional literary critic, Homer Whipple, which is said to have been written in 1959.

Read the wikipedia article. It makes more sense but still a mindfuck

You picked the wrong guy to ask.