The interaction paradigm is a new conceptualization of computational phenomena that emphasizes interaction over algorithms, reflecting the shift in technology from main-frame number-crunching to distributed intelligent networks with graphical user interfaces. The book is arranged in four sections: "Introduction," comprising three chapters that explore and summarize the fundamentals of interactive computation; "Theory" with six chapters, each discussing a specific aspect of interaction; "Applications," five chapters showing how this principle is applied in subdisciplines of computer science; and "New Directions," presenting four multidisciplinary applications. The book challenges traditional Turing machine-based answers to fundamental questions of problem solving and the scope of computation.

The interaction paradigm is a new conceptualization of computational phenomena that emphasizes interaction over algorithms, reflecting the shift in technology from main-frame number-crunching to distributed intelligent networks with graphical user interfaces. The book is arranged in four sections: "Introduction," comprising three chapters that explore and summarize the fundamentals of interactive computation; "Theory" with six chapters, each discussing a specific aspect of interaction; "Applications," five chapters showing how this principle is applied in subdisciplines of computer science; and "New Directions," presenting four multidisciplinary applications. The book challenges traditional Turing machine-based answers to fundamental questions of problem solving and the scope of computation.

The ECOOP '91 Workshop on Object-Based Concurrent Computing was organized toprovide a forum on concurrent, distributed and open-ended computing. The emphasis was on conceptual, theoretical and formal aspects, as well as practical aspects and sound experience, since such a viewpoint was deemed indispensible to investigate and establish a basis for future development. This volume contains 12 papers selected from 25 presented at the workshop, together with a paper by J.A. Goguen, who was an invited speaker at the workshop. The papers are classified into four categories: Formal methods (1): three papers are concerned with the formal semantics of concurrent objects based on process calculi. Formal methods (2): four papers are concerned with various formal approaches to the semantics of concurrent programs. Concurrent programming: three papers. Models: three papers areconcerned with models for concurrent systems.