I recall reading this as a teenager. I didn't really understand it then, and revisiting it more than thirty years later was an odd experience, as I expected to find a real classic I'd previously misunderstood. But I didn't. To start with, I'd forgotten how abrupt, terse, and awkward Dick's writing style was back in the early 60s. This is not an easy book to read, or fathom. I'd forgotten how the plot skitters about from one character to another (a strength, I know, for some readers) and how stereotyped some of them are (he even has a Japanese say "ah so"!) I'd forgotten the Nazi spy plot and how impenetrable it is, altogether.
Dick was always at his best when detailing the actions of the little man, in this case Frank Frink, who loses his job and begins his own jewellery business. He's good when detailing relationship breakdowns - the passages featuring Frank's ex-wife, Juliana, and her quest for the 'Man in the High Castle' were also fascinating. He's always interesting when indulging in religious speculation, here done via the I Ching. But once he strays into a kind of John le Carre spy world involving top ranking (though not historical) Nazis I think he loses his way. He certainly lost me.
Fakes abound in this book, from the fake guns - which can still kill - fake American artifacts, and fake people. No one is who they seem to be: one character is visited by a representative of a Japanese admiral, who isn't really a representative at all; he's Frank Frink. But Frink isn't really Frink, he's Fink, a Jew, and so in great danger from the authorities. And so on. Finally, there's the 'Man in the High Castle' himself, and his curious book, 'The Grasshopper lies heavy' - a title adapted from the Bible - wherein Germany and Japan actually lost the war. But even that book is a fake, in that it is not 'our' world. Maybe this novel too is a fake? Maybe reality itself cannot be trusted, and may be a fake - which was doubtless what Dick was getting at. I just wish he'd written these marvellous ideas down in a more readable way.