The design and the verification of modern software applications requires the analysis of several different aspects, such as software correctness, quality of service, and security, and of the possible inter-relations among them. Process algebraic architectural languages and the related analysis techniques provide a formal paradigm that allows for the modeling and analysis of such systems and of the related properties during the early stages of the design process. The book presents such a paradigm in a novel way that privileges the discussion of its foundational characteristics and then introduces a number of guidelines, integrated with ad-hoc methodologies and exemplifying case studies, to support the practical benefits of using such a paradigm. The book can be of help for both researchers and graduate students who intend to approach the process algebraic formal paradigm and for the practitioners who intend to apply the related approach to software design and verification.