What function is played by concepts related to meaning and mereology in the cognitive sciences? How can one outline adequate simulation models for the continuous emergence of new categorization forms characterizing cognitive processes? To what extent is it possible to define new measures of meaningful complexity? How is it possible to describe synergetically the symbolic dynamics inherent in cognitive processes? What types of formal models should we use to describe the evolutionary aspects of cognition? These, the most difficult questions in cognitive science, are discussed here in 15 original essays written by distinguished scholars drawn from a variety of disciplines. The first part presents an up-to-date account of some current trends in the functional modeling of cognitive activities, the synergetic models in particular are widely discussed. The second part focuses on recent advances in complexity theory, self-organizing networks, the theory of self- reference, and the theory of self organization. The third part focuses on some methods of formal analysis that can be used to delineate consistent simulation models of cognitive activities at the perceptual, linguistic and computational levels. The volume also highlights traditional philosophical concerns about realism, the cognitivism-connectionism debate, and the role of holistic assumptions. Readership: psychologists, cognitive scientists, theorists working in complexity theory, self-organization theory, synergetics, semantics of natural language and mereology, philosophers, epistemologists.