It seems to deal with the complexity of these questions of belief, as noted in this excerpt from the first part of the review:
This raises the question (and it is a crucial one) of whether labels such as atheist or Unitarian or Catholic or misotheist really capture a religious identity as an essence: something stable that defines the whole person. Or, alternatively, is it really possible to shuttle between different religious or anti-religious positions without abandoning the notion of identity altogether or doing away with (theo-)logical consistency?
I believe that fiction has the unique ability to put our noses squarely on such big questions, and that it does so in a way that seems merely the by-product of a story rather than its declared purpose. Indeed, works of literature like The Book Against God are uniquely positioned to get us involved in the conundrums of human belief and to make us ask critical and deeply relevant questions about matters of spirituality, faith, the mind, behavior, and values.
I tend to disagree with the last part of the review where he talks about reading a work as some type of psychological profile of the author. I can see where that is meaningful when you are trying to analyze the author; but not really when you are trying to understand the work. I think E L Doctorow said something like, "My book is successful not if it tells you something about me, but rather if it tells you something about you." I tend to enjoy literature from that light.