For centuries, the first five books of the Bible (Genesis through Exodus) were thought to have been written by Moses. However, in the mid-1800s, a scholar named Julius Wellhausen noticed that there were four distinct writing styles among these books and that some stories were told more than once with different language, emphases, and details. For example, there are two distinct creation stories, two versions of the flood, two accounts of God’s covenant with Abraham, etc. This led Wellhausen to hypothesize that there are four primary writers or schools of writers who authored these books. These authors are referred to by the first letter of the names Wellhausen gave them. “J” is shorthand for the writer he named “the Yahwist” (a name beginning with a “J” in German). This writer is so named because he used the name Yahweh when referring to God. “E” refers to the “Elohist,” a writer who used the name “Elohim” for God. “D” stands for the “Deuteronomist,” the author of much of the material in the book of Deuteronomy. Finally, “P” is for the “Priestly” writer, one recognized by a penchant for recording religious rituals and cultic practices.
Without advanced theological studies it is difficult to parse out exactly who wrote what in the Old Testament, and even biblical scholars still argue about the authorship of particular passages. In general, however, the JEDP theory is well-accepted for its broad categorization of different strands of writing which give us insight into different ways of approaching and relating to God.