This is a book which covers the ground which Richard Dawkins was accused of failing to cover in his excellent The God Delusion, but as Dawkins himself mentioned in that book, it was never his intention to do that since it had been done already - in books such as this one! Note that these arguments are not new (indeed, the copyright on this one is some forty years old), and some of them go back to antiquity, but the refutations still stand as strong as ever since nothing new or original has arisen to overturn these.
The author opens with a discussion of the scope of atheism and the concept of a god, and then specifically looks at the god of Christianity. In part two, he considers reason versus faith, the varieties of faith, and the revelation. Part three addresses the arguments for a god tackling them one after another: those from natural theology, from a first cause, from contingency, and from design: a non-argument which has been much popularized lately by those who are clueless about science and who call themselves creation scientists. Trust me, there is no such thing as creation science unless the definition of science is changed by faith so that it equates to 'carping about things you don't like and can refute neither by logic nor by counter evidence'.
He concludes with a discussion of the practical consequences of belief and the sins of Christianity.
I recommend this as a worthy read, but please note that you can these days find pretty much everything this book contains online.