It was Dawkins' rebuttal of all pro-God arguments
and pretty much said that if you believed in a religion you were narrow-minded and dim.

EDIT: I just realised that you probably meant what was The Selfish Gene about, not God Delusion. The Selfish Gene was about the gene being the unit of inheritance rather than the individual organism, so explaining behaviour that seems illogical - an individual might die to save their relatives, thus continuing the gene. Bad explanation, sorry. Good book though.
( in vino veritas, Tue 7 Jul 2009, 22:35, archived)