This volume presents important results of the Collaborative Research Center (Sonderforschungsbereich) "Situated Artificial Communicators," which was funded by grants from the German Research Foundation (Deutsche Forschungsgemeinschaft) for more than twelve years. The contributions focus on different aspects of human-human and human-machine interaction in situations which closely model everyday workplace demands. The authors are linguists, psycho- und neurolinguists, psychologists and computer scientists at Bielefeld University. They jointly tackle questions of information processing in task-oriented communication. The role of key notions such as context, integration (of multimodal information), reference, coherence, and robustness is explored in great depth. Some remarkable findings and recurrent phenomena reveal that communication is, to a large extent, a matter of joint activity. The interdisciplinary approach integrates theory, description and experimentation with simulation and evaluation.