The End of Faith
by Sam Harris
That's a very provoking and controversial book. It's a critique of organized religion and it's impact on society. One of the important points made by the author is the thesis that religions and beliefs are the main source of conflict in the world. The author also suggests that criticism of religious beliefs should not be subject to freedom of speech.
For me, it's good to have other people perspective on such important matter. Even if I'm not religious person at all, I obviously consider religion to be a very important factor that motivates and is shaping the view of billions of people. If you are a religious person, this book may be harsh and bit offensive.