Introduction: More/Less Theology is the Problem/Solution. He apparently seeks a middle ground between religious conservatives and the "New Atheists" -- apparently liberal theology and "New Age" beliefs.
Chapter One: Science Fiction on Theology; Science Fiction as Theology. After discussing the issue of the existence of God, he continues with discussing "transcendent outsiders" and how critical of us they can be on account of our numerous misdeeds. Yet they are not necessarily punitive, but disappointed in us as if we were misbehaving children.
Chapter 2: Aliens as Traditional Gods. The authoritarian and judgmental and punitive sort. RC discusses The Day the Earth Stood Still (1951) in this connection. Klaatu is clearly a Jesus-Christ figure in it. But Gort is much like like some authoritarian god, even extending to his willingness to use force.
Then H.G. Wells's War of the Worlds (1898), about Martians trying to conquer Britain. Though some people have criticized him for making the story mostly set in Britain, it was appropriate in some ways. Britain was then the biggest world power, ruling over a larger land area and a much larger population than itself, despite losing thirteen rebellious North American colonies a little over a century earlier. RC argues that the book is an allegory for imperialist and colonialist arrogance, and I think that he's correct about that.Klaatu: For our policemen, we created a race of robots. Their function is to patrol the planets in spaceships like this one and preserve the peace. In matters of aggression, we have given them absolute power over us. This power cannot be revoked. At the first sign of violence, they act automatically against the aggressor. The penalty for provoking their action is too terrible to risk. […] I came here to give you these facts. It is no concern of ours how you run your own planet, but if you threaten to extend your violence, this Earth of yours will be reduced to a burned-out cinder. Your choice is simple: join us and live in peace, or pursue your present course and face obliteration. We shall be waiting for your answer. The decision rests with you.