Who wrote the book of Genesis? (Overview)

Because of the strong tradition that Moses was the author of Genesis, the best way to answer the question is to establish whether it was likely, or possible that Moses wrote the book then, if Moses was not really the author, consider who else might have written the book.

Samuel Davidson, D.D, in An Introduction to the Old Testament, Critical, Historical, and Theological, Containing a Discussion of the Most Important Questions Belonging to the Several Books (published 1862), identified several clear lines of evidence that Genesis can only have been written long after the time of Moses. Among these:

A. Words that obviously imply that when the writer lived, the Canaanites and Perizzites had been expelled from the land -

Genesis 12:6:And Abram passed through the land unto the place of Sichem, unto the plain of Moreh. And the Canaanite was then in the land.
Genesis 13:7: And there was a strife between the herdmen of Abram's cattle and the herdmen of Lot's cattle: and the Canaanite and the Perizzite dwelled then in the land..

B. Hebron is the name almost always used in Genesis, yet the city did not get that name until Caleb changed the name of the city from Kirjatharba to Hebron, meaning that this name is posterior to Moses:

Genesis 23:2: And Sarah died in Kirjatharba; the same is Hebron in the land of Canaan: and Abraham came to mourn for Sarah, and to weep for her.
Joshua 14:14-15: Hebron therefore became the inheritance of Caleb the son of Jephunneh the Kenezite unto this day, because that he wholly followed the LORD God of Israel. And thename of Hebron before was Kirjatharba; which Arba was a great man among the Anakims. And the land had rest from war.

C. In Genesis 14:14, Abraham is said to have pursued the kings who carried away Lot his nephew, as far as Dan. But we learn from Joshua 19:47 and Judges 18:29, that the name of the place was Laish, until the Danites possessed it and called it Dan, "after the name of their father."

D. Davidson says that, because of Genesis 36:"31, the book could hardly have been written before there reigned any king over the land of Israel:

Genesis 36:31: And these are the kings that reigned in the land of Edom, before there reigned any king over the land of Israel.

E. Here Jacob is referring to the "land of the Hebrews" at a time when it was supposedly the land of the Canaanites, a mistake Moses could scarcely have made:

Genesis 40:15: For indeed I was stolen away out of the land of the Hebrews: and here also have I done nothing that they should put me into the dungeon.

This is far from the totality of evidence that Moses did not write the Book of Genesis, but it is enough to be conclusive.

In the nineteenth century, Julius Wellhausen carried out stylistic analyses, and was able to assign authors called J (the 'Yahwist') and E (the 'Elohist') to the nature and fertility stage of religion, D ('Deuteronomist') to the spiritual and ethical stage, and P ('Priestly Source') to the priestly and legal stage. At the same time, historical analysis suggested that J was the earliest source, E somewhat later, and D and P centuries later than J. We can leave out the Deuteronomist, who is considered to have had little or no input to the Book of Genesis. Subsequent scholars have challenged Wellhausen's hypothesis, but Mark S. Smith says in The Early History of God (page xxiii) that it has not been supplanted by a more persuasive model. Lester L. Grabbe, in Ancient Israel (page 44) says that many would still agree that Genesis was compiled mainly from three sources – the Yahwist (J), the Elohist (E) and the priestly writer (P).

Some modern scholars suggest modifications to Wellhausen's hypothesis, but almost all are in general agreement. The consensus is that the Yahwist wrote in around the ninth century BCE, the Elohist in the eighth century BCE but definitely before the fall of Israel in 722 BCE and the Priestly Source during or shortly after the Babylonian Exile. These writings were then redacted into more or less the form we know today, by the Redactor. The redacted compilation is definitely post-Exilic and so belongs to the period around the fifth century BCE.

Genesis/Exodus/Leviticus are a compilation of several narratives, all dating to the 10th century BC or thereabouts, which are evident by the seams in them, and by the radically different styles. They are considered to be compiling Jewish narratives to make a unified tale which will bring the disparate tribes together in a kingdom.

There are three major threads:

Yahwist (J)

This author is first rate, one of the greatest writers in history, if not the greatest. She writes about God in a very visceral, fully embodied fasion. She tends to emphasize the stories of women, providing first person internal monologues from the point of view of Eve, Rebecca, Sarah, and provides a wonderful story of female attempted seduction in Genesis 39. For this reason, I refer to her as a "she", although this is obviously uncertain.

You can identify J easily by reading the narrative. There is no doubt when she is writing. She consistently uses "Yahweh" as God's name, or "Yahweh God" in Genesis 2. She writes internal monologue and easy natural dialogue. She tends to write stories of women in detailed human terms, and of men in distant heroic terms.

The quintessential Yahwist narrative is exemplified by the following passage in Exodus, chapter 33, verses 17, in my translation, available here :

And Yahweh said to Moses: "Also this thing that I have spoken I will do, because you are pleasing to me, and I will know you by name."

And he said: "Please show to me, your honor."

And said, "I will bring by all my goodness in front of you, and I will call on the name of Yahweh in your presence, and I will grace that which I will grace, and I will feel for that which I will feel for."

And He said: "You could not see my face, because a man will not see me and live."

And Yahweh said: "Here is a place filled with me, and you will post yourself against the rock. And it will be as mine honor will pass, and I will put you in the nook of the rock, and I will lean my palm against you until I pass.And I will remove my palm, and you will see my back, but my face will not be shown."

The idea of seeing God's back, as He is moving away, lifting an enormous palm from a nook in the rock to uncover his mighty passing form, is simultaneously beautiful and haunting, and masculine erotic.

Elohist (E)

Elohist has a less fleshy description of God than J, and the drama is not as tense. Elohist writes about blessings and omens a lot. Here is some E (Genesis 48, in my translation, available on Wikisource ):

And Joseph took the two of them, Ephraim in his right hand, to the left of Israel, and Menashe in his left hand, to the right of Israel, and he approached him. And Israel sent his right hand and placed it on Ephraim's head, and he is the younger, And his left hand on Menashe's hand: with consideration upon his hands, because Menashe is firstborn.

And he blessed Joseph, and said: "The God in whose presence my fathers came before, Abraham and Isaac, the God who has shepharded me from before until this day, the angel who spares me from all harm, will bless these youths, and will call into them my name, and the name of my forefathers Abraham and Isaac, and they will multiply in the face of the land."

And Joseph saw that his father had sent his right hand on the head of Ephraim--- and this was wrong in his eyes. And he supported his father's hand to take it off the head of Ephraim, to Menashe's head. And Joseph said to his father, "Not so, father, because this is the firstborn, put your hand on his head."

And his father declined, and he said: "I knew, my son, I knew. He also will be a great nation, and he also will grow in number; but his younger brother will grow more than him, and his seed will fill the nations."

E uses "El Shaddai", which is a weird monicker for God. He also has the extraordinary "I am that I am" (more literally, "I'll be what I'll be"), which is followed by a Yahweh tack-on with an obvious seam.

Priestly (P)

Priestly can't write to save his life. He is almost surely a Levite priest, who is trying to canonize Leviticus law by attaching it to the timeless masterpieces produced by J and E. Priestly's voice is heard at the end of Exodus and throughout Leviticus.

A typical Priestly passage (Leviticus 11, vs 41-45) in my translation, available on Wikisource:

And all the vermin that infests the Earth, it is an abomination, it will not be eaten. All the walks on its torso, and all that walks on four, unto any centipede, onto all the vermin that infests the earth--- you will not eat them, because they are an abomination. Do not abominate your souls in all the vermin that infests, and do not defile in them, and you were defiled by them. Because I am Yahweh your God, and you were blessed holy and became holy, because I am holy. And you will not defile your souls in all the vermin that crawls on the earth. Because I am Yahweh, who raises you from the land of Egypt, to be a god for you, and you became blessed holy, because I am holy.

This block is particularly repetitive, but even this example does not do justice to Priestly's cloying, unnecessary, mind numbing repetitions. Things are a "comforting smell to Yahweh" six times in a chapter, detailed grilling instructions are repeated, detail by detail, three times for three only slightly different situations. Priestly is boring, uninspired, pedantic, and generally unreadable. One of the best things about Christianity is that you can ignore nearly everything he wrote.

Priestly is also the master of stilted narrative. Here is Leviticus Chapter 10 (my translation, on Wikisource) :

And the sons of Aaron, Nadav and Avihu, each took from their sinstuff and they put fire to them, and they put incense upon it, and they sacrificed before Yawheh, on a foreign fire, which was not commanded of them. And a fire came out from before Yahweh, and consumed them, and they died before Yawheh.

And Moses said to Aaron: "That is what Yahweh spoke, saying: that with me I shall bless, and in front of all the people, I will be respected." And Aaron fell silent.

And Moses called to Mishael and Eltzaphan, the sons of 'uzi-el, Aaron's uncle, and said to them: "approach and carry your brethren from facing the holiness, to outside the camp." And they came close, and they carried them in their cloaks, to outside the camp, as Moses spoke.

This is so stilted and badly written. Aaron's sons are immolated in his presence, and there is none of the drama of Lot running from the fire and brimstone, pleading with God to let him find shelter in a Mizar. None of the beauty and elegance of Jacob's pining for his lost son, prayed by wolves. No sign of the genius of pacing or drama of Genesis and the early half of Exodus. Their crime basically amounted to cooking communal meat on a grill different from the communal grill.

The only line of genius which can be safely attributed to Priestly is Leviticus 19:18 (in generic translation--- I went with "You loved your compatriot as yourself", but this phrase is famous.)

"And you loved your neighbor as yourself"

This is surely his, because it is embedded in a set of verses that repeat "I am Yahweh" for no good reason again and again and again.

Redactor (R)

The Redactor is whoever put the narratives together to make a whole. This is probably Priestly, the way I see it. You can see the redactor at work at several places, where verses are inserted for no reason other than the discomfort of the editor at what is being said.

consider Genesis 18, verses 16-22 in my Wikisource translation:

And the men stood from there, and they gazed towards Sodom, and Abraham walked with them, to send them off.

And Yahweh said: "I disguise from Abraham that which I am doing,

And Abraham, onwards will be a great big people, and through him all the nations of the Earth will be blessed.

Because it was known to him that which he commanded his sons and his household to do, and they kept the way of Yahweh, to make charity and justice--- leading to Yahweh bringing Abraham that which he spoke to him about.

And Yahweh said, "the cry of Sodom and Gomorrah is so loud, and their sins, so very heavy. I will descend there and see if its cries which comes to me are due to them all; and if not, I will know it."

And the men turned from there, and did go towards Sodom; and Abraham, still left standing before Yahweh.

There is an obvious break in the otherwise extraordinarily beautiful narrative, coming right after "I disguise from Abraham that which I am doing." The thing that God wishes to disguise from Abraham is the destruction of Sodom and Gommorrah, but as the angels walk toward the city, Abraham argues with God about the destruction.

Anyway, redactor didn't like that God is diguising something from Abraham, and so stuck in the completely inane two verses that follow, which simply repeat promises of God to Abraham from other passages, which are completely out of context here.

Unlike other translations, the translation above seeks to preserve the tone-deaf narrative and horrible writing style of redactor, which match the tone-deaf narrative and horrible writing style of Priestly. I don't see any reason to think they are separate authors.

There is also the issue of the "and Aaron"'s in Exodus. These read more naturally if omitted, so that God is speaking to Moses only. But the Exodus author tacks on "and Aaron" in many places, some places where it mismatches with the singular tense of the verb! This is R at work, although I don't see any reason why this isn't P.

Arguing against identifying R with P is the fact that while common authorship of writing of great genius is easy to identify, all hacks of the same era write alike.

Others

There is supposedly a D author, the Deuternomist, who continues the narration into Deuteronomy and perhaps Judges. I didn't translate those books, so I can't judge.

As for other authorial guesses, I think that the author of psalm 137 is also the author of lamentations, either in whole or in part. The word choice and the strange baby imagery is so distinctive.

Tradition says Moses compiled the book of Genesis, along with writing the rest of the Torah.

However from Wikipedia:

Tradition credits Moses as the author of Genesis, Exodus, Leviticus, Numbers and Deuteronomy, but the books are in fact anonymous and look back on Moses as a figure from the distant past;[3] some traditions contained in Genesis are as old as the United Monarchy, but modern scholars increasingly see it as a product of the 6th and 5th centuries BC.[4]

It is rather unclear who actually put the words to paper.

This Answers in Genesis article argues that Moses did indeed write Genesis:

Ultimately, the author of Genesis was God, working through Moses. This does not mean that God used Moses as a ‘typewriter’. Rather, God prepared Moses for his task from the day he was born. When the time came, Moses had all the necessary data, and was infallibly guided by the Holy Spirit as to what he included and what he left out. This is consistent with known history, and with the claims and principles of Scripture (2 Timothy 3:15–17; 2 Peter 1:20–21).

The answers in Genesis article claims to prove this conclusively. However, I think the best we cay say is that we are unsure.