Political and social trust are often seen as important determinants or elements of a functioning democracy and citizens well-being. But what is trust, and how it actually influences citizens and the political system? The purpose of the course is to give students a comprehensive picture of the concept of trust and its relevance in political science. The course starts with a conceptualization of trust, both as a political and social concept. After the conceptualization, measuring trust is analysed, and main results concerning survey evidence on trust discussed. The course goes then on with discussing the relevance and role of trust in international relations, trust in comparative perspective, the relationship of trust to political inequality and its relevance in explaining the rise of right wing populism. The course provides students analytical tools to study trust and an extensive knowledge of the relevant literature.