The knowledge approach in information processing is the phenomenon of the last years and offers more sophisticated organization of data and information and more effective retrieval to information than traditionally databases or internet web pages. Knowledge base (KB) of the knowledge management system is defined in ontology that has more dynamic and complex view on data than database schema in database management. Information in KB is related together so that is in complex shape and information retrieval is performing in network from one piece of information to the other piece. The publication provides an overview of selected concepts of information and knowledge management and knowledge systems, continues in the description of taxonomy, vocabulary, thesaurus, and ontology. After that follows chapter on theoretical and practical bases that includes The Topic Maps principle and the ATOM software description. The actual core of the book consists of the ontology development and description of two ontology driven applications. First is MilUNI ¿ portal for cooperation of military universities and the second is the mini-application for support of innovation process.