Religious diversity is part and parcel of the world we live in today. In many countries, adherents of different religions and denominations coexist with nondenominational people and with atheists. At the same time, religion plays an important international role in the coexistence of different states and cultures. Thus one of the primary challenges faced by modern society is to ensure the peaceful coexistence of people from different cultural and religious backgrounds. The question of where people fi nd common ground and what gives them security and guidance has occupied my mind for many years. On my travels and in my encounters with people of widely divergent backgrounds, faiths, and biographies, I am always struck by the variety of human experience. This variety is a precious good in its own right that we should take care not to jeopardise.