The God Delusion (Richard Dawkins)
[Dec 25, 2008; Book]
I walked by this book a couple of times because - being an atheist - I wasn't really expecting any news. But finally I gave in to the hype, got a copy and did not regret it.
Dawkins put together a really well structured and by all means complete set of arguments against religion, quite a few of which were new to me. Especially his refusal to accept agnosticism as a valid point of view. His writing - while eloquent - is a bit to mild on the subject for my taste. (This was also pointed out by a great Southpark episode.) But he makes up for it by quoting a variety of other authors when its time for a giggle. Here are two examples:
The Devil's Dictionary (Ambrose Bierce):
to pray: to ask that the laws of the universe be annulled in behalf of a single petitioner, confessedly unworthy
The End of Faith (Sam Harris):
We have names for people who have many beliefs for which there is no rational justification. When their beliefs are extremely common we call them 'religious'; otherwise, they are likely to be called 'mad', 'psychotic' or 'delusional' ... Clearly there is sanity in numbers.
One impressive example he mentions on the creation of religions are Cargo Cults. They demonstrate how easily humans make up new religions and are recent enough to prove that there was nothing supernatural involved in their making, only misinterpreted observation. See links below.