The Themes of The Book of Devorim

This Shabbos we will start reading the Book of Devorim. Which is Anglicized as Deuteronomy (which means basically, review)
but is translated as "words".
It is Moshe Rabeinu's final words to the Jewish people who he faithfully led for the past 40 or so years.
Every year I try to find the pattern and themes of the Book of Devorim.

I have not been successful.

I do not believe this is the uncontrolled ramblings of an old man.
I know that there is a rhyme and reason for how and why Moshe says what he says and when.
There needs to be a theme for each Parsha, for example. And even though there are repetitions of certain concepts many times, they have to be repeated for a contextual reason.
The choice laws that Moshe reviews here have to be done for a certain purpose. Why certain laws were reviewed and others not. Why that particular Parsha in which those laws are reviewed is chosen, also has to have meaning.
For instance why the Laws of Kashrus in Parshas Reah, etc.

In this week's Parsha, Moshe recounts the story of the Jewish people in the desert, going in order, starting from before the receiving of the Torah when he structured the Court system, then the spies, and then suddenly at Chamishi, he jumps approx 40 years to the end of the the Bnei Yisroels travels to the conquering of the various lands that were conquered. Why?

So I think that basically over the years I have come to understand maybe the theme of the first 3 Parshas.
Devorim - the Am Yisroel, the people.
V'eschanan - the Torah
Ekev - The land of Israel.
But it is not exclusive or conclusive.
And then???
Your thoughts are welcome.