Chart - JEDP Diagram
The Four Sources of the Pentateuch - The Torah
At first, scholars thought that there were only two earlier documents, one called the Yahwist source, and the other the Elohist source, based on the way each referred to God's name. But it soon became clear that Genesis and the Exodus also contained a priestly cast to it, against the other that contained many of the old stories involving historical traditions. Now there were three sources, and it didn't take long to identify a fourth.
The unique style of the Book of Deuteronomy set it apart from the other three. These four sources are called by their first letters J, E, P, D. The 'J' instead of the 'Y' comes from the German word Jahve, for it was German scholars who first proposed the abbreviations.