Siren and amelinda make some points that I would like to iterate on: religion is a matter of faith. There is no empirical evidence that supernatural powers exist, nor is there any empirical evidence that supernatural powers do not exist; therefore, logically, nothing can be said about the existence of supernatural powers. So belief of any sort, including unbelief, is inherently non-logical.
The book that Seqram refers to is, in light of the above, making a logical error. One's beliefs about that which cannot be proved or disproved are neither logical nor illogical.
I'm not quite sure why the author doesn't extend the courtesy of being convinced to one's own satisfaction to atheists.
S'funny, I have twice in the past couple of years been suddenly overcome by the incredibly strong feeling that there is no such thing as the supernatural, that there was no god or gods. It was kind of a sucky feeling, because the concept of oblivion after death is really boring to me. Though I have not had any such strong feelings to the contrary; i.e., that there was a higher power, I continue merrily in my paganism with the tiny scraps of inspiration that I sometimes attribute to the supernatural.
There is one other thing to keep in mind: arguments for the existence of "the one truegod", whether they pretend to be based in logic or fully acknowledge that they are philosophical, are forgetting one important detail:
How do you know there's only one god? How do you know that this supernatural being is, in fact, conscious and looking out for us? In short, how can anyone claim to know the nature of god or the supernatural?