Who is D from Who Wrote the Bible? and what is their importance?

D is said to be the author of Deuteronomy and parts of the rest of the Pentateuch. Friedman identifies D as Jeremiah. Jeremiah also likely pulled together or wrote the next six books after the Pentateuch. The style of D tends toward a just, but transcendental, God who never walks upon the earth with men. Snakes do not talk in D literature either.