Why are the Jewish scriptures broken into named "books"

[rgprice]

Why are the scriptures of Deuteronomistic history organized into "books"? Fundamentally, the works of Deuteronomistic history are an account of the origins of the nation of Israel. Other such national histories that I know of are not organized the way that the Jewish scriptures are. They are typically organized by number or something along those lines. Where exactly do the names come from and how are they designated in the earliest manuscripts?

[Secret Alias]

First word.

Bearshit.
Shemop.
Vacuum cleaner.
Be-mindful.
Deviled ham.