This volume brings together the peer-reviewed contributions of the participants at the COST 2102 and euCognition International Training School on "Multimodal Signals: C- nitive and Algorithmic Issues" held in Vietri sul Mare, Salerno, Italy, April 22 -26, 2008. The school was sponsored by COST (European Cooperation in the Field of Scientific and Technical Research, www.cost.esf.org) in the domain of Information and Communi- tion Technologies (ICT) for disseminating the advances of the research activities developed within Action 2102: "Cross-Modal Analysis of Verbal and Nonverbal Communication" (www.cost.esf.org/domains_actions/ict/Actions/Verbal_and_Non- verbal _Communication) and by euCognition: The European Network for Advancement of Artificial Cognitive Systems (www.euCognition.org). COST Action 2102, in its second year of life, brought together about 60 European and 6 overseas scientific laboratories whose aim is to develop interactive dialogue systems and intelligent virtual avatars graphically embodied in a 2D and/or 3D int- active virtual world, able to interact intelligently with the environment, other avatars, and particularly with human users. The main theme of the school was to investigate the mathematical and psycholo- cal tools for modelling human-machine interaction through access to a graded series of tasks for measuring the amount of adjustment (as well as intelligence and achie- ment) needed for introducing new concepts in the information communication te- nology domain in order to develop adaptive, socially enabled and human-centered automatic systems able to serve remote applications in medicine, learning, care, re- bilitation, and for accessibility to work, employment, and information.