When it comes to the issue of God, you are in two camps. Either you believe or you don't. It is extremely difficult to convince a person otherwise; they must simply come to their own conclusions. I say this because if I were to give a copy of this book to a religious friend, they would most likely not change their views. Which is a pity, as I am of the same belief as Hitchens that religion and belief in God is an archaic system that made sense of the world when we didn't understand it but really has no place in today's world.
Saying that, Hitchens did not touch upon the fact that religion does give some people hope and inspiration to their lives. I don't think that everyone is ready for a world where there is no supreme being, no rewarding afterlife and no 'comfort'. Personally I don't need any of that, I feel perfectly comfortable living my life the way I want it without the need to submit myself to some higher being who apparently is a bit of a egoist given he demands worship and cruelly punishes those who are not of his sect. But, not all people are like me. Authors such as Dawkins would label them as weak, which I think is stupid as you will not change someone's mind by insulting them. The main problem I have with it is that organised religion is so restrictive. Let's say that God exists. If he is going to send me to hell for eating pork, what kind of a god is he in the first place? I think that it is a great pity that so many people in the world live lives cowed in submission, denied simple pleasures because their god has forbidden cutting their hair/drinking/eating pork/petting a dog/medicine, etc. etc. etc. And so does Hitchens.
This is a marvelously witty book which seeks to spell out as clearly as possible that religion is a man-made institution and that it has served its purpose. He makes the point that if one religion is true and all others false, why bother? You are just as likely to go to hell, so you may as well enjoy yourself whilst you are here (ok that might be more my thoughts coming through). One can be a gentleman and have morals and not be religious. He spends most the time focusing upon the monotheistic religions, but does address the eastern ones too which I found very interesting. Particularly as I loathe people in the US and UK who decide that Western = bad and that Hinduism/Buddhism are much better. I bet they never looked into how the Dalai Lama repressed Tibet for centuries.
Overall, I would recommend this book to anyone (although I actually listened to the audiobook read by Hitchens himself). It is witty, well-written and extremely thought provoking. I doubt it would make many religious people recant, but it is a good and accurate summation of the reasons of why I am an atheist. One of my favourite points from the book was that religions demand respect and reverence from those outside of it, but never treat those outside the same. That for me sums up why it is an archaic and stagnated set of beliefs which have held the development of the world back. Religion might not poison everything, but it certainly makes things more difficult.