In many states the role of religion and religious communities is controversial. While this is particularly true of predominantly Muslim countries, it also holds for Europe. The controversy revolves not least around the issue of religious instruction. What is the legal basis of religious instruction, in which institutions does it take place, who draws up the curricula, who trains the teachers, and what is its impact? Do states seek to instrumentalise it to strengthen their legitimacy; do societal forces use it to influence government policies? Does it trigger, deepen or reduce conflict? These questions are examined in case studies of Afghanistan, Bosnia-Herzegovina, Egypt, France, Germany, India, Indonesia, Israel, Lebanon, Macedonia, Tunisia, Turkey and the UK. A comparison of the case studies reveals commonalities in the pattern of problems and conflicts, but also gaps in the state of our knowledge, and, hence, the need for further research.