Book of Deuteronomy have given various answers to the problem. The Deuteronomistic history theory is currently the most popular (Deuteronomy was originally just the law code and covenant, written to cement the religious reforms of Josiah, and later expanded to stand as the introduction to the full history); but there is an older theory which sees Deuteronomy as belonging to Numbers, and Joshua as a sort of supplement to it. This idea still has supporters, but the mainstream understanding is that Deuteronomy, after becoming the introduction to the history, was later detached from it and included with Genesis-Exodus-Leviticus-Numbers because it already had Moses
On Weights and Measures translated the Book of Genesis, another two the Book of Exodus, another two the Book of Leviticus, and so forth, until the entire 22 canonical books of the Hebrew Bible had all been translated into the Greek tongue. The seventy-two translators were drawn from the twelve tribes of Israel, six men to each tribe who were skilled in the Greek language. In folios [49a–50a] Epiphanius gives a description of the canonical books of the Hebrew Bible and translations made of the same. In his day, he notes that the Scroll of Ruth and the Book of Judges were joined together,