I'm actually not quite done with the book, but the last chapter is more of an addendum, discussing bioethics for Christians, so it's not well connected to the rest of the book. At this point, I feel it fair to review the main argument of the book. I can't fault Collings as a scientist. The guy helped crack open the human genome! As a philosopher, however, he leaves me wanting.
There are three general parts to the book. In part I, Collins writes about his own journey of faith, borrowing heavily from CS Lewis' Mere Christianity to describe how he left atheism, and describe the general conflict of worldviews inherent in the "evolution vs. Christianity" battle. Part II is Collins' attempt to describe the more recent findings of science as they relate to the conflict (cosmology, microbiology, etc.) and either show how they work to the advantage of Christianity or use them to rebut the arguments of literalist creationists.
It's in this part that I start to feel frustrated with the book. Though Collins' is right to keep a firm grasp on the science and use it to knock down some of the loonier arguments made by others, I feel that he abuses some of the arguments. He constantly harps on the "God of the Gaps," assigning God as a black box to cover up anything we don't understand. Which is fine, he rightly finds this argument lacking. However, I fear he takes it too far.
If you believe that God is in control of the universe, that no atom vibrates without God's approval, then it is not wrong to say that God causes some phenomena. It strikes me as unfair to confuse the agent and the mechanism, but Collins bundles them together everytime. Collins simply takes to task those who would insert "a miracle" (i.e. magic) when asked for the mechanism.
In a related note, Collins also does not handle the Creationist arguments well. Essentially, when using the complexity of the human genome to point out the evidence for human evolution and common ancestry, he continually asks, "Why would God do X if we weren't descended from a common ancestor?" This is a poor argument, stemming from the same logical fallacy as the question of evil ("Why does God allow evil?"). It results in someone saying, "God couldn't have done this because I wouldn't do it this way." But can you presume to know the mind of God so much as to say so? Would you limit God so much? Granted, the argument does have some merit, but Collins handles it poorly.
Finally, in part III, Collins explores the four philosophical possibilities, and explains why his works and the others don't. They are Atheism, Creationism, Intelligent Design, and Theistic Evolution (or BioLogos, as he prefers to call it). I'll give Collins credit that he spends a chapter or two examining Genesis and quoting Augustine in arguing for a non-literal interpretation of the text. However, I'm afraid he never takes things all the way.
Collins never fully explains what his position is. He tends to float around it, arguing for the existence of God and the truth of evolutionary theory (and all that goes with it), but then doesn't really go much further. There's a bit of flowery, poetic language about how beautiful and graceful life and science are and how God couldn't be anywhere else but there, but he declines to go into further detail. When it comes to the heart of his philosophy, he leaves it at, "God does evolution."
I'm not sure he ever intended to go further in the book with his philosophy than that, or whether he himself has explored it any further. The major purpose of the book was to show that Christianity must not be antithetical to science, and that science does not disprove Christianity. This he does a decent job of, but he leaves people who have already reached those conclusions hanging at the end of the book.
If you've not explored the general Science vs. God philosphy before then the book makes a great introduction for you, especially if you're in either of the camps described in the paragraph above. However, for people like myself, trying to nail down the specifics of where theology and science must ultimately coincide, the book will not answer many questions.
I give it a 6/10. Good, not great.