What are the root causes of intolerance? This book addresses that question by developing a universal theory of what determines intolerance of difference in general, which includes racism, political intolerance, moral intolerance and punitiveness. It demonstrates that all these seemingly disparate attitudes are principally caused by just two factors: individuals' innate psychological predispositions to intolerance ("authoritarianism") interacting with changing conditions of societal threat. The threatening conditions, particularly resonant in the present political climate, that exacerbate...