Tricky question. The God in question is the God with a connection to the world history. It's had prophets and "attempted contacts" both.
If you believe history that is.
The thing is that when someone states that they don't believe in God, they are actually saying they don't believe in what people say about God.
I know this, because if I were to explain God in the way I understand it you would have to admit that this thing I speak of makes sense, because I would define everything completely. But you wouldn't be able to find a single word in any historical or religious text that can disprove it. You'd find plenty to verify it though.
I realize that my choice of words and angle in this post reek of presumption. But I am actually saying that when most people do not grasp the concept of God it is because of inaccurate history, misunderstood prophets and deliberate misdirection to gain power among men, not God, and that is pretentious. No disguising that.