The interaction paradigm provides a new conceptualization of computational phenomena that emphasizes interaction rather than algorithms, thus reflecting the shift in technology from number-crunching on mainframes to distributed intelligent networks with graphical user interfaces. Editors Goldin, Smolka and Wegner have structured 18 contributions from distinguished researchers into four sections: "e;Introduction"e;, consisting of three chapters that explore and summarize the fundamentals of interactive computation; "e;Theory"e; with six chapters, each discussing a specific aspect of interaction; "e;Applications"e; showing in five chapters how this principle is applied in various subdisciplines of computer science; and "e;New Directions"e; presenting four multidisciplinary applications beyond computer science. The book challenges traditional Turing machine-based answers to fundamental questions relating to problem solving and the scope of computation. Assuming the reader has only an undergraduate-level background in computer science, it serves as an introduction to this increasingly important discipline.