Personal, secretly informative, fragmented
Because of the "POV" of The Man of the High Castle, we get all of our information through people's eyes (and biases). For instance, when Tagomi goes to the Japanese government lecture on the potential leaders of Nazi Germany, we get several reminders of how terrible most of these dudes are; that is, because Tagomi is the one hearing this lecture, we get to listen in on his feelings about all this information:
Mr. Tagomi felt ill as he listened. […]
Mr. Tagomi thought, I think I am going mad. (6.166, 170)
These aren't subtle hints about how Tagomi is feeling. The book comes right out and tells us. That's what we mean when we say the style is personal. Here's another example of how we get information through the characters: when Frank hears the radio talk about some German "effort," Frank fills in the facts and his feelings.
He knew which particular effort the radio had in mind. Yet, there was after all something humorous about it, the picture of stolid, grumpy Germans walking around on Mars, on the red sand where no humans had ever stepped before. Lathering his jowls, Frink began a chanting satire to himself. Gott, Herr Kreisleiter. Ist dies vielleicht der Ort wo man das Konzentrationslager bilden kann?(1.53)
Check out that paragraph. As you might have noticed, some of it isn't even in English, because Frank speaks German (and also Yiddish). That explains why his POV sections have a sprinkling of foreign words. (The German here is one Nazi asking another about building a concentration camp. On Mars. For Martian Jews.) That's very personal. But that paragraph is also secretly informative. It tells us that the Germans are about to start colonizing Mars. There's a lot of information buried in this novel, though it might be buried in someone's memories or someone's reactions.
Lastly, The Man in the High Castle's style is fragmented, which we mean in the best way. We get a lot of fragments on the sentence level when we listen in to people's thoughts. In fact, sometimes the fragmented sentences clue us in about the fact that we're listening to a thought, like when we hear about Childan being overwhelmed by an emotion:
It was all he could say. Lunch, in one of the downtown businessmen's fashionable restaurants. He and this stylish modem high-place young Japanese. It was too much; he felt his gaze blur. (7.56)
"It was all he could say" and "It was too much; he felt his gaze blur" are complete sentences. But the two sentences in the middle are fragments, which indicate that they are Childan's thoughts.
But The Man in the High Castle is also fragmented on the chapter level. Many chapters include different characters' POVs, and there's not always a clear connection between these fragments. For instance, take the blackmailing of Wyndham-Matson. First, we get Frink and McCarthy planning something, but we don't hear what (4.70); then, from Childan's POV, we see someone come in and expose the fakes in his store (4.108). Now, eventually, we learn that this person was Frink and that spooking Childan was part of the blackmailing. But when we first read the book, we may not see the direct connection between these fragments.
Did you notice we used the phrase "POV" here a bunch? That's because Dick's style depends so much on his choice of point of view (POV). For more on that, you can check out "Narrator Point of View."