What is the truth about human nature? Are we each born a blank slate upon which experience is written? Steven Pinker here argues that our usual explanations of human behaviour - stated most clearly in the human sciences of psychology, ethics and politics - tend to deny what is now undeniable: the role of an inherited human nature. Differences in personality or achievement, whether seen among races, ethnic groups, sexes or individuals, are routinely explained away as due not to differences in innate constitution but differences in experience. This work argues otherwise.