In this book, Hussmann builds a bridge between the pragmatic methods for the design of information systems and the formal, mathematical background. Firstly, the principal feasibility of an integration of the different methods is demonstrated. Secondly, the formalism is used as a systematic semantic analysis of the concepts in SSADM, a British standard structured software engineering method. Thirdly, a way of obtaining a hybrid formal-pragmatic specification using a combination of SSADM notations and formal (SPECTRUM) specifications is shown. This well-written book encourages scientists and software engineers to apply formal methods to practical software development problems.