Russell considers a number of logical arguments for the existence of God, including the first-cause argument, the natural-law argument, the argument from design, and moral arguments. He also goes into specifics about Christian theology.
His final conclusion: "Religion is based, I think, primarily and mainly upon fear. It is partly the terror of the unknown and partly, as I have said, the wish to feel that you have a kind of elder brother who will stand by you in all your troubles and disputes. ... A good world needs knowledge, kindliness, and courage; it does not need a regretful hankering after the past or a fettering of the free intelligence by the words uttered long ago by ignorant men."