Sam Harris, atheist extraordinaire, tackles a difficult question with his newly minted doctorate in neuroscience: Can science—or rather, the scientific method—make definitive statements about human morality? Harris says absolutely; the criticism for this book arises from the unwillingness of many readers to examine the way words like moral are defined or to accept Harris’ definitions. He keeps it simple, though; morality is determined by how a particular action affects the well-being of other conscious beings. You’d think most people would buy that, but apparently not if it means divorcing morality from the list of rules created by whatever invisible being one has accepted as God. Inevitably, this becomes a discussion about reason, one that’s no doubt meant to counter the canard that atheists can have no morality without a belief in a higher power. Harris isn’t trying to “win”; he’s trying to define the parameters for a conversation, and he has succeeded admirably.