I don't want to sound judgemental, but this is a book only someone in marketing or advertising could have written.
First of all, there's the conceit and arrogance. History's greatest philosophers have spent years thinking about God and millions of words attempting to understand and explain the idea. But Paul Arden can do it in about one hundred pages? That seems unlikely.
Secondly, there's the simplistic, childish approach and layout. In advertising, there's value in presenting your ideas in short, punchy pages, because you're presenting simple ideas: buy this, think that. In philosophy, you're not trying to sell anything, and any attempt to reduce complex ideas to the level of an advert is bound to miss the point.
I find it difficult to understand why this book was published, other than the obvious and reductive reason that people might pay money for it. It's a collection of vague, random thoughts on God and religion, with no obvious organisation or direction. Here's a page that suggests building a mosque at ground zero; there's one with St. Anselm's proof of God's existence (with the footnote that the "proof" might require "another taxi ride to think about!", when in fact it could be countered by a child, or in a two panel comic). Each brief thought is given its own two page spread. The only insightful comment is marketing related, which speculates that Scientologists are perhaps more committed because they have invested more.
Finally, Arden gets to his point. Something caused our universe to come into existence, call it "creation" or "evolution" or "chance"; these are just names, as is "God". So why not call it "God"? But giving something a name doesn't explain anything - whereas actually, those other names do at least embody an attempt at explanation (and real explanations are complex).
This is a simple book for simple minds. It's tempting to say that it's by a simple mind. Paul Arden appears to have been a successful advertising executive, but judging by this and what I have seen of his other books, his skill is in stating the obvious in simple, attractive ways. There's no depth here - and, ultimately, no explanation.