The course aims to give the student the knowledge necessary to understand the development of the concept of "different" in history, both from a cultural and a biological point of view. Furthermore, prejudices and stereotypes must be examined and discussed, as they are linked to personal identity formation. Some of the many cases present in contemporary society consist of national characteristics attributed to individuals and groups based on scarce imprecise information, without insights and rationalizations on the characteristics of a people. Equally negative are attitudes towards physical and mental disabilities, and particularly serious are racism and xenophobia. The course aims to provide a critical view of what is usually presented as cultural and biological differences within human groups, to dispel some preconceptions sometimes present in our society.