A good book to read that addresses this whole issue, and its short too, is "If I were God I'd make myself clearer" (2002) by Australian; John Dickson. The first sentence of the blurb on the back reads: "If there really is something spiritual out there, wouldn't there be some pretty clear signposts to it?" and it says; "John Dickson considers the vast array of spiritual claims made by different religions and individuals and asks whether any clarity about God can be found."
Another book, that is slightly longer, and a very interesting read is "Is God past his sell-by date" (2002) by American author John Blanchard, which he writes in the preface is a "book specifically intended for atheists, agnostics and others with serious doubts about the existence of God."