Well, it's likely a satirical or critical take on the Bible stories from an atheist perspective. It might analyze and question the traditional interpretations and the religious dogma associated with those stories.
The 'Atheists Book of Bible Stories' probably aims to expose what atheists see as the contradictions, implausibilities, or perhaps the historical inaccuracies in the Bible stories. It could be a way for atheists to engage with religious texts in a way that challenges the religious establishment. For example, it might question the miracles described in the Bible, such as the parting of the Red Sea, by looking at it from a scientific or rational point of view.