The topic of this volume was discussed at a Round Table of the International Association for Dialogue Analysis (IADA) at the University of Bologna in March 1995. The Round Table was intended to make a scientific contribution in honour of the president's 65th birthday. The topic refers on the one hand to the central problem of 'Dialogue Analysis' which is to discover a new, communicatively functioning unit after having left behind the unit of the sentence which can be considered the unit par excellence of structural linguistics. On the other hand, it includes the manifold units, relations, and strategies, i.e. the specific problems of dialogue analysis.