The development of information processing systems requiresmodels, calculi, and theories for the analysis ofcomputations. Complex software systems are best constructedin a careful, systematic, and disciplined structuring of thedevelopment process. Starting from basic requirementspecifications in which all the relevant details areformalized, the envisaged solution should be developed stepby step by adding more and more details and giving evidenceor formal proofs to show the correctness of the steps, untila description of a solution is obtained that has all therequired properties. The Marktoberdorf Advanced Study Institute 1992 presentedscientific highlights in approaches to the systematic studyofreliable software and hardware systems using functional, algebraic, and logical calculi. Leading scientists treatedthe specification, development, verification, andimplementation of complex time-sensitive systems, such assignal processing systems, process control systems, andgeneral software systems. The mathematical foundations ofspecification and refinement were carefully treated, andseveral formalisms for describing processes were introduced. Emphasis was put on application-oriented descriptionsof signal processing systems with real-time dependencies. Formalisms for reasoning about distributed causality-basedcomputations were presented and new styles of programmingleading to shorter and more expressive notations weredemonstrated. This book is based on the Institute, and gives an impressivedemonstration of the state of the art and the essentialprogress in our formal abilities to specify, refine, verify, develop, and implement complex software systems includingembedded systems and hard real-time dependent systems.