This hypothesis was developed in the 18th/19th century and proposes four sources
- J (Yahwist)
- E (Elohist)
- P (priestly)
- D (deuteronomist)
J and E are so-named because of the forms of the divine name that dominate in the passages ascribed to them. Most of the book of Leviticus, and other passages having to do with the operation of the sacrificial system, are ascribed to P. The familiar "JEDP" ordering was the contribution of Julius Wellhausen, although the basic division had already been worked out before him.
The four source theory has fallen into disfavour in the 21st C. Many schloars had already thought E insuffciently distinguishable from J to merit separate status, so "JE" was the common designation. Meanwhile, P seemed the most distinctive, and some specialists now prefer to speak only of "P" and "non-P" material.
What once seemed a settled and assured result of scholarship appears this way no longer. For further information, see Wikipedia.