This book develops a general theory of intolerance of difference.What is the basis for intolerance? This book addresses that question by developing a universal theory about what causes intolerance of difference in general, which includes racism, political intolerance (e.g. restriction of free speech), moral intolerance (e.g. homophobia, supporting censorship, opposing abortion) 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.What is the basis for intolerance? This book addresses that question by developing a universal theory about what causes intolerance of difference in general, which includes racism, political intolerance (e.g. restriction of free speech), moral intolerance (e.g. homophobia, supporting censorship, opposing abortion) 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.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 authoritarian attitudes include, most critically, great dissension in public opinion and general loss of confidence in political leaders. Using purpose-built experimental lcA