The Documentary Hypothesis proposes that the first five books of the Hebrew Bible (Genesis, Exodus, Leviticus, Numbers, and Deuteronomy, known collectively as the Torah or Pentateuch), represent a combination of documents from four originally independent sources. According to the influential version of the hypothesis formulated by Julius Wellhausen (1844–1918) these sources and the approximate dates of their composition were:

• the J, or Jahwist, source; written ca. 950 b.c.e. in the southern kingdom of Judah. (The name Yahweh begins with a “J” in Wellhausen’s native German.)
• the E, or Elohist, source; written ca. 850 b.c.e. in the northern kingdom of Israel.
• the D, or Deuteronomist, source; parts written ca. 720–620 b.c.e. in Jerusalem during a period of religious reform, and other parts written after 587 b.c.e..
• the P, or Priestly, source; most parts written ca. 550 b.c.e. by Aaronid priests, but other parts may be from traditions of one or two hundred years earlier.

The editor who combined the sources into the final Pentateuch is known as R, for Redactor, and might have been Ezra.