The goal of contemporary cognitive science is not primarily to build a thinking machine, but to increase our understanding of cognitive processes. This can be done by various methods, including traditional psychological experiments, observations of authentic cognitive processes in practical action, or by simulating cognition in robots or programs. Unlike the early days of AI when it was believed that one single methodology, that of symbolic representation, could solve all cognitive problems, the current trend is to work with several forms of representations and data. The publication is the result of a collaboration between the Department of Cognitive Science at University of Lodz and the Department of Cognitive Science at Lund University. It is intended to provide a comprehensive presentation of the key research issues undertaken in both Departments, including considerations on meaning, natural language and reasoning, linguistic as well as numerical competence, the theory of decision making, modelling of conceptual representations, cognitive and game theoretic approach to social interactions. The book is addressed to all readers interested in cognitive science, and especially in research combining a logical analysis with psychological, linguistic and neurobiological approaches.