This volume describes how to experimentally determine and interpret the rheological behaviour of polymer melts, then analyze flow in processing operations. It develops the fundamentals of continuum mechanics and shows how to devise methods for measurement of rheological properties, formulation of 3-dimensional stress-deformation relationships and analysis of flow in processing operations. The structure of polymers is described and rheological behaviour interpreted in terms of these structures. The book also discusses polymer fabrication technology and how to analyze and design these processes. Each chapter comprises a critical historical survey followed by a concise development of the topic.