Book excerpt: This book constitutes the joint refereed proceedings of seven international workshops held as part of OTM 2004 in Agia Napa, Cyprus in October 2004. The 73 revised papers presented together with 31 abstracts of posters from the OTM main conferences were carefully reviewed and selected from more than 150 submissions. In accordance with the 7 workshops, the papers are organized in topical sections on grid computing and its applications to data analysis; Java technologies for real-time and embedded systems; modeling inter-organizational systems; regulatory ontologies; ontologies, semantics and e-learning; PhD symposium; and interoperability.