With a new book falling on a Saturday, I pulled a couple of commentaries off the shelf before diving into the reading. Just like the Gospels each have a unique perspective that informs our reading of them in modern time, so do the books of the Old Testament. Deuteronomy, it seems is a part of a polished Hebrew tradition, likely rooted originally in the reign of King Josiah around 600 BCE.
The book is connected with Joshua, Judges, 1-2 Samuel and 1-2 Kings (aka "Former Prophets") that can be called the Deuteronomic history "because they explicitly presuppose a tradition of divinely given law by which events and persons are judged."
The work, however, was clearly edited significantly during the Babylonian exile, and even refers to it within the next. This creates the very interesting juxtaposition of a work explicitly describing the people of God preparing to enter the Promised Land for the first time, with the people of God preparing to return to the Promised Land after exile.
Sources: New Interpreter's Study Bible, Introduction Book of Deuteronomy, Ronald E. Clements (1998); The Old Testament World, Legal Texts, John W. Rogerson and Philip R. Davies (1989) *Old, I know, but it is very hard to search the internet for reliable Biblical commentary.