Karen Armstrong's In the Beginning is a depressing performance all around. It's hard to believe that the same writer who gave us A History of God, that brilliant and multifaceted introduction to Western monotheism, could have penned this weak and predictable "new interpretation" of Genesis. Rather than interpretation, In the Beginning is an exercise in interpolation. The author inserts a vaguely progressive ethics in the interstices she can find in the ancient text of Genesis. The results are not convincing and, as far as I'm concerned, they're not progressive either.
What is the intent behind this kind of work? My best guess is that Armstrong is here trying to make the first book of the biblical canon "relevant" for modern readers. She's trying to demonstrate how the stories in Genesis dramatize many of the same "issues" that (supposedly) concern us. Unfortunately Armstrong does this by betraying Genesis. Her interpretations are not adequate to an ancient Semitic scripture. Certainly a scholar as widely read as Armstrong knows very well how anachronistic Noah and Abraham and Sarah and Jacob appear in the outfits she puts on them. So why has she undertaken such a dressing up? For whose benefit?
The texts that make up Genesis strike us by their radical otherness, their inconsistencies and uncanny strength (the paradox of their inconsistencies/strength). There is powerful artistry both in the writing of Genesis and in the editing that established its final biblical form. By trying to domesticate the book the way Armstrong does--by schematizing family relations according to modern psychologies of trauma, by submitting the ancient writers' representations of God to modern political ethics--Armstrong offers us an essay unworthy of its subject. What is worthwhile in her book is not really new, and most of what is new is unpersuasive as interpretation.
Read A History of God, which demonstrates Armstrong's great powers as a teacher and writer. But if you're interested in interpretation of the book of Genesis, look elsewhere. Robert Alter's excellent edition of the text would be a good place to start.