A fil rouge goes through Habermas’s decade long research. It is the idea that Reason and rationality permeate human societies and may lead human action towards emancipation, if aptly elaborated through the filter of theoretical reflection. Theory must pick up on this rational core and turn the intrinsic rational potential inherent to modern societies into a self-consciously pursued ‘project of enlightenment’. This introduction to the special issue ‘Habermas, Democracy, and the Public Sphere: Theory and Practice’ shows how Habermas’s work in (...) different scientific domains contributes to the construction of the ‘project of modernity’ from the many angles that such a complex project requires. The public sphere is, in Habermas’s theory, the societal domain in which communicative interactions have a chance to make Reason come to bear on human societies and lead them on the path to social and political emancipation. The contributions to this special issue focus therefore on the public sphere and illustrate the evolution of the concept in Habermas’s work and its relation to democracy at national and supranational level. (shrink)