The book initially presents the basic concepts related to the Semantic Web, Semantic Web-based applications, Web applications, Ontology, and their qualitative aspects. It then presents the evaluation of the structural quality of modular ontologies and review on metrics for the evaluation of ontology behavior. Further, the book discusses the qualitative evaluation of Semantic Web applications deployed on the Cloud, helping readers understand, maintain, integrate, and reuse these applications. The book offers software engineers in general and ontology engineers in particular a single, valuable guide to help them find the best modularization on the basis of goodness of (re) use. It can also serve as an initial source of information for starting research in this domain.