Walter Moberly's study Guide to Genesis 12-50 provides an invaluable introduction to the second part of Genesis and is essential reading for anyone interested in the patriarchal narratives and the earliest history of the people of Israel.
Other than being somewhat dated, this is an excellent survey of ways that Genesis 12-50 is and has been viewed. It tends to defend the historicity of the patriarchs and brings interesting ideas to the table such as understanding how those who finally wrote down the text of Genesis used various names for God to make points rather than just interweaving strand of text. The understanding Temple Judaism had of Genesis is also addressed cleverly.