Book excerpt: The two-volume set of LNCS 6426/6427 constitutes the refereed proceedings of 3 confederated international conferences on CoopIS (Cooperative Information Systems), DOA (Distributed Objects and Applications) and ODBASE (Ontologies, DataBases and Applications of SEmantics). These conferences were held in October 2009 in Greece, in Hersonissos on the island of Crete. CoopIS is covering the applications of technologies in an enterprise context as workflow systems and knowledge management. DOA is covering the relevant infrastructure-enabling technologies and finally, OSBASe is covering WEB semantics, XML databases and ontologies. The 83 revised full papers presented together with 3 keynote talks were carefully reviewed and selected from a total of 223 submissions. Corresponding to the OTM main conferences the papers are organized in topical sections on process models and management, modeling of cooperation, services computing, information processing and management, human-based cooperative systems, ontology and workflow challenges, access control, authentication and policies, secure architectures, cryptography, data storage and processing, transaction and event management, virtualization performance, risk and scalability, cloud and distributed system security, reactivity and semantic data, ontology mapping and semantic similarity, domain specific ontologies.