The underlying idea of the book is that most ordinary religious believers -- not philosophers or theologians -- do not realise how weak the case for Gods existence is. The Case Against examines the reasons why the belief has such a strong hold on so large a section of humanity, and attempts to show that the reasons are inadequate. The concepts involved in religious belief are examined in detail. It is shown that great difficulties -- of which believers are usually unaware -- are involved in forming concepts of entities from a higher -- perhaps spiritual -- realm. In particular, God and the idea of a life after death are examined and it is proposed that viable, coherent concepts are probably impossible in both cases. For many believers the God theory is seen as (a) explaining the origin of the universe, and (b) enabling the apparent injustices of this world to be righted in a life after death. The theory actually fails to do either. It is also shown, however, that the main alternative to theism, which is materialism, itself presents difficulties. No final answer is given, and it is accepted that (informed) puzzlement may ultimately be the only rational position. The God theory could perhaps be seen as an attempt to answer genuine problems. While it fails, it can nevertheless be understood and treated with sympathy. God: The Case Against is not intended for philosophers or theologians! Rather, the aim is to make the arguments accessible to intelligent, intellectually curious, open-minded people. The book attempts throughout to give clear, simple explanations of the issues, benefiting here from the authors own experience in teaching philosophy to young people.