Pentateuch

Pentateuch means the first five books of the Bible. These books are Genesis, Exodus, Leviticus, Numbers, and Deuteronomy. The word "Pentateuch" comes from two Greek words that mean "five books" or "five scroll" 
According to tradition, the books were written by the Israelite leader, Moses. The Pentateuch is often called the Five Books of Moses or the Torah.
The Pentateuch tells the story from the Creation of the world to the death of Moses and the preparation of the Israelite's to enter the land of Canaan. The story is told in three parts. The first part (Genesis 1-11) is about the Creation and the beginning of human beings on earth. The second part (Genesis 12-50) are the stories of the ancestors of the Israelites, mainly Abraham, Isaac, Jacob, and Joseph. The third part, beginning with the book of Exodus, describes how the Israelite's left Egypt and the early history of the people of Israel as a nation. It also has many laws about how the Israelite's must build their society. Deuteronomy is mostly Moses's final speech to his people and a summary of the Pentateuch.
The Pentateuch is most likely the oldest part of the Bible, however there is speculation that the book of Job could be older due to the similarities of Job to the patriarchal period, ie counting wealth in flocks and the sacrifices being performed by the patriarch of the household rather than a priest. Scholars do not know exactly when these books were written however many place Moses at between 1,600 - 1,450 BC. The earliest parts may have been written more than 1,000 years before the final parts according to the Julius Wellhausen 4 JEDP theory. However this theory is based on the idea that the Pentateuch is a disjointed work and has received due criticism. Modern archaeological discoveries suggest that some of the oldest stories in Genesis may date back three thousand years.