Basic info on Documentary Hypothesis (origin of Torah)

Documentary Hypothesis (also known as JEDP) proposes that the first five books of the Old Testament (Genesis, Exodus, Leviticus, Numbers and Deuteronomy, known collectively as the Torah or Pentateuch) represent a combination of documents from originally independent sources.

Development of the hypothesis arise from attempts to reconcile inconsistencies in the ancient texts of the Torah. According to the influential version of the hypothesis formulated by Julius Wellhausen (1844–1918), there were four main sources, and one final redaction. These sources and the approximate dates of their composition were:

• J, or Jahwist, source; written c. 950 BC in the southern kingdom of Judah. (The name Yahweh begins with a J in Wellhausen's native German.) The writings where likely based on early oral and written sources, maybe even original from cultures outside of Israel.
• E, or Elohist, source; written c. 850 BCE in the northern kingdom of Israel. J and E may have been combined at some point after the fall of the northern kingdom of Israel in 722 BCE.
• D, or Deuteronomist, source; written c. 621 BCE in Jerusalem during a period of religious reform. P, or Priestly, source; written c. 450 BCE by Aaronid priests.
• R, or Redactor, source; written c. 400 BCE by the last editor(s) who combed the what was available from the previous sources to combine them in to the final Pentateuch. This editor may have been Ezra.
  

According to Wellhausen, the four sources present a picture of Israel's religious history, which he saw as one of ever-increasing centralization and priestly power. In effect, this exposes a de facto conspiracy by the individuals in the various eras to shape the documents to suit their contemporaneous needs.

Although rejected by most Judaism and Christian faiths (for fairly obvious reasons), modern forms of Wellhausen's original hypothesis have become the dominant scholarly view on the origin of the Pentateuch. Most contemporary Bible experts accept some form of the Documentary Hypothesis, and scholars continue to draw on Wellhausen's terminology and insights. In the area of New Testament scholarship, proposed solutions to the synoptic problem often bear a strong resemblance to the Documentary Hypothesis.

References:

http://www.cs.umd.edu/~mvz/bible/doc-hyp.pdf

http://www.religioustolerance.org/chr_tora1.htm