The public discourse is often hardened. The same can be observed in the ecumenical context. Here and there the accusation of fundamentalism is quickly at hand. Is fundamentalism just a polemical labelling of positions that do not correspond to one's own? Or can the term be used to describe political and religious groups that pursue a clearly discernible agenda? The present anthology pursues these questions by reflecting in its various contributions on the conceptual history and the meaning of fundamentalism in different geographical, denominational and religious contexts.