The documentary hypothesis (DH) 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 four originally independent sources. According to the influential version of the hypothesis formulated by Julius Wellhausen these sources and the approximate dates of their composition were:
the 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 E, or Elohist, source; written c. 850 BC in the northern kingdom of Israel;
the D, or Deuteronomist, source; written c. 621 BC in Jerusalem during a period of religious reform;
the P, or Priestly, source; written c. 450 BC by Aaronid (from A’aron lineage) priests.
The editor who combined the sources into the final Pentateuch is known as R, for Redactor, and might 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. Wellhausen’s hypothesis became the dominant view on the origin of the Pentateuch for much of the 20th century. Most contemporary Bible experts accept some form of the documentary hypothesis, and scholars continue to draw on Wellhausen’s terminology and insights .
After Wellhausen. For much of the 20th century Wellhausen’s hypothesis formed the framework within which the origins of the Pentateuch were discussed, and even the Vatican came to urge that “light derived from recent research” not be “neglected”, listing specifically “the sources written or oral” and “the forms of expression”.  Some important modifications were introduced, notably by Albrecht Alt and Martin Noth  , who argued for the oral transmission of ancient core beliefs – guidance out of Egypt, conquest of the Promised Land, covenants, revelation at Sinai/Horeb,  etc. Simultaneously, the work of the American school of biblical archaeologists such as William F. Albright and Cyrus Gordon seemed to confirm that even if Genesis and Exodus were only given their final form in the first millennium BCE, they were still firmly grounded in the material reality of the second millennium.  The overall effect of such refinements was to aid the wider acceptance of the basic hypothesis, by reassuring believers that even if the final form of the Pentateuch was not due to Moses himself, and,
“despite the late date of the Pentateuch, we can nevertheless recover a credible picture of the period of Moses and even of the patriarchal age. Hence opposition to the documentary hypothesis gradually waned, and by the mid-twentieth century it was almost universally accepted.” 
The collapse of the consensus began in the late 1960s, with the spread of new scholarly tools and a growing recognition of the limitations of Wellhausen’s analytical framework. The result has been proposals which modify the documentary model so far as to become unrecognizable, or even abandon it entirely in favor of alternative models which see the Pentateuch as the product of a single author, or as the end-point of a process of creation by the entire community. Thus, to mention some of the major figures from the last decades of the 20th century, H. H. Schmid almost completely eliminated J, allowing only a late Deuteronomical redactor;  Rolf Rendtorff and Erhard Blum saw the Pentateuch developing from the gradual accretion of small units into larger and larger works, a process which removes both J and E, and, significantly, implied a supplemental rather than a documentary model for Old Testament origins;  and John Van Seters, using a similar model, envisaged an ongoing process of supplementation in which later authors modified earlier compositions and changed the focus of the narratives.  With the idea of identifiable sources disappearing, the question of dating also changes its terms.
The challenge to the Wellhausen consensus was perhaps best summed up by R. N. Whybray, who pointed out that of the various possible models for the composition of the Pentateuch – documentary, supplemental and fragmentary – the documentary was the most difficult to demonstrate, for while the supplemental and fragmentary models propose relatively simple, logical processes and can account for the unevenness of the final text, the process envisaged by the DH is both complex and extremely specific in its assumptions about ancient Israel and the development of its religion. Whybray went on to assert that these assumptions were illogical and contradictory, and did not offer real explanatory power: why, for example, should the authors of the separate sources avoid duplication, while the final redactor accepted it? “Thus the hypothesis can only be maintained on the assumption that, while consistency was the hallmark of the various documents, inconsistency was the hallmark of the redactors!”  Richard Elliott Friedman’s  “Who Wrote the Bible?” (1987)  and “The Bible with Sources Revealed” (2003)  were in essence an extended response to Whybray, explaining, in terms based on the history of ancient Israel, how the redactors could have tolerated inconsistency, contradiction and repetition, indeed had it forced upon them by the historical setting in which they worked. Friedman’s classic four-source division differed from Wellhausen in accepting Yehezkel Kaufmann’s dating of P to the reign of Hezekiah; this in itself is no small modification of Wellhausen, for whom a late dating of P was essential to his model of the historical development of Israelite religion. Friedman argued that J appeared a little before 722 BCE, followed by E, and a combined JE soon after that. P was written as a rebuttal of JE (c. 715-687 BCE), and D was the last to appear, at the time of Josiah (c. 622 BCE), before the R-Redactor, whom Friedman identifies as Ezra, collated the final Torah.
Antony F. Campbell and Mark A. O’Brien’s “Sources of the Pentateuch” subsequently presented the Pentateuchal text sorted into continuous sources following the divisions of Martin Noth. But while the terminology and insights of the documentary hypothesis continue to inform scholarly debate about the origins of the Pentateuch, it no longer dominates that debate as it did for the first two thirds of the 20th century.
 Harris, Stephen L., Understanding the Bible. Palo Alto: Mayfield. 1985.
 Let the interpreter then, with all care and without neglecting any light derived from recent research, endeavor to determine the peculiar character and circumstances of the sacred writer, the age in which he lived, the sources written or oral to which he had recourse and the forms of expression he employed.” Encyclical Divino Afflante Spiritu, 1943
 Martin Noth (1902 –1968) was a German scholar of the Hebrew Bible who specialized in the pre-Exilic history of the Hebrews. With Gerhard von Rad he pioneered the traditional-historical approach to biblical studies, emphasising the role of oral traditions in the formation of the biblical texts.
 Albecht Alt, “The God of the Fathers”, 1929, and Martin Noth, “A History of Pentateuchal Traditions”, 1948.
 Albright W.F., The Archaeology Of Palestine. Hardmondsworth: Penguin, 1949
 Wenham Gordon., Pentateuchal Studies Today Themelios 22.1 (October 1996): 3-13.
 Schmid, “Der sogenannte Jahwist” (“The So-called Yahwist”), 1976.
 Rendtdorff, Rolf. The Problem of the Process of Transmission in the Pentateuch, Journal for the Study of the Old Testament Supplement 89, 1990.
 Van Seters, John “Abraham in History and Tradition”, 1975.
 N. Whybray, “The Making of the Pentateuch”, 1987, quoted in Gordon Wenham, “Exploring the Old Testament”, 2003, pp.173-174.
 Richard Elliott Friedman is a biblical scholar and the Ann and Jay Davis Professor of Jewish Studies at the University of Georgia. He joined the faculty of the UGA Religion Department in 2006. Prior to his appointment there, he was the Katzin Professor of Jewish Civilization: Hebrew Bible; Near Eastern Languages and Literatures at UCSD from 1994 until 2006
 Friedman Richard Elliott ., “Who Wrote the Bible?” HarperCollins Publishers 1987
 ___________ The Bible with Sources Revealed: A New View into the Five Books of Moses , Harper San Francisco, 2003.
 Kaufmann, Yehezkel “The Religion of Israel, from Its Beginnings to the Babylonian Exile”, 1961.