Does he offer any substantial evidence that our way of thinking is wrong and there must be a Theistic being out there, or is it just another angry Christian rant against Atheism and different stream of thoughts like most of these books are?
I skimmed a good chunk of it while I was working at Borders. As I recall, he doesn't presume to demonstrate that God exists or even probably exists, which is a little refreshing. (Dinesh D'Souza, on the other hand, in "What's So Great About Christianity," tries to pull some nonsense like, "The Big Bang had a cause, so I'll just go ahead and refer to it as a 'creation,' so of course it probably has a creator, and besides, we don't really have any solid evidence for the Multiverse theory, so there. Oh, and Kant said something about an unknowable transcendent reality, which seems to be rather indicative of God/Heaven, wouldn't you say?")
Instead he spends a lot of time calling out Dawkins/Harris/Hitchens on some of their more shaky arguments, and he sometimes seems to do a pretty good job, e.g. on Dawkins's "Why There Almost Certainly is no God," in which Dawkins makes the leap from, "All complex organisms evolved by simple and non-miraculous means," to, "The Universe itself almost certainly evolved by simple and non-miraculous means." He also insists that an intelligent creator would have
to be more complex than whatever it creates. He calls this argument "irrefutable," which is only true in the sense that the contrary apparently can't be proved. I do find his premises and conclusion exceedingly difficult to doubt, but that can rarely be the case with theists, and it's all too easy to say that arguments based on inductive reasoning are never conclusive.
I think the author also says some stuff about how atheists have faith in science and lack an ultimate rational foundation for their moral behavior, which isn't totally
nonsensical. I mean, I have only a cursory understanding of the naturalistic theories of our origins, and I couldn't begin to defend them in terms of my own observations and inferences about nature; my confidence in the validity of evolution, for instance, rests on multiple appeals to authority: Almost every scientist accepts evolution (which I haven't personally confirmed, but have seen attested to by multiple sources whose credibility I don't recall being questioned), and scientists often make the assurance that scientists are generally faithful to the endlessly self-critical ideals of science.
And as for morality, I wouldn't hesitate to admit that my reluctance to harm a sentient being is apparently just a very strong feeling; as far as I can tell, nobody's rationally obligated to disapprove of murder, unless they happen to feel like maximizing the feelings we commonly recognize as happiness and peace, which they again aren't rationally obligated to feel like maximizing.
He also points out some historical instances in which scientific knowledge has been (partially) responsible for great destruction, e.g. the atom bomb. I didn't bother to remember the exact point he was trying to make, probably an attack on the secularist's perceived position that scientific knowledge is generally for the best and should be freely pursued. Whatever, I don't feel like getting into that. Like D'Souza, he spends a lot of time looking at the social and historical aspects of the theism/atheism debate, which have never really concerned me a whole lot, since they're basically irrelevant to the question of whether god-belief is intellectually warranted.
If there's anything to take from the book, it's that we don't have an airtight philosophical defense for everything we do and believe (but you'd have to be extremely pedantic for that to really affect your actions and beliefs).