Christians consider their religion virtually synonymous with morality, believing there can be no moral standard without a God to guarantee it, no moral behavior without belief in God and knowledge of his commandments. Disbelievers are objects of their suspicion, tarred with labels like "relativist" and "nihilist." But buried under the benign and placid surface of their own theology lies a ticking moral time bomb, and most of them have never realized the sinister implications of what they purport to believe. Having his loins girt with a lifelong regard for rational truth, wearing the...