The papers contributed by the participants from 29 countries and printed in this volume were reviewed by the members of the international scientific committee. The main topics of the conference are represented by epistemology of knowledge organization, information and knowledge in e-society, knowledge representation, engineering and management aspects of knowledge organization (with the focus on knowledge organization), classification schemes, taxonomies and categorization schemes, thesauri, semantic networks and ontologies, knowledge organization systems for understanding, sense-making and learning, knowledge organization systems for decision support systems, knowledge organization systems for knowledge discovery in very large datasets, data modeling for the semantic Web, organization of linked data, indexing and retrieval in multilingual environments, organization of unstructured information, multimedia in knowledge organization, Web indexing and social tagging, user needs in knowledge organization, automatic categorization and indexing, history of knowledge organization and ISKO, knowledge organization for the future.