This book discusses, carefully but in a way that the general reader can follow, the main arguments for and against the existence of God. These include the traditional ontological, cosmological, and design arguments from consciousness and from morality, and on the other side the problem of evil. They also include Berkeley's distinctive case for theism, and Hume's argument against there being adequate evidence to support the belief in anything miraculous. As well as the older versions, newer versions of the traditional arguments and newer approaches are examined. These include Plantinga's modal version of the ontological argument, Swinburne's inductive versions of several arguments, the reliance on religious experience, the arguments of Pascal and William James for voluntary belief, and Kierkegaard's advocacy of non-rational commitment.