Polymers are now an important class of engineering material, present in almost every manufactured product.They also have distinctive physical properties and manufacturing routes, in many respects quite different from those of other engineering materials such as metals.Hence the subject of engineering with polymers has become an essential ingredient of the skill set of many of today's professional engineers.This book is designed to help teaching and learning of the subject of Polymer Engineering.It is especially focussed on the relevant aspects of materials science, mechanical engineering and production engineering, at a level of expertise typical of advanced undergraduate or postgraduate students of engineering or materials science.The authors' aim is to provide an educational tool, not only conveying information but also engaging the reader and developing their confidence and skills by applying, in the polymer engineering context, their wider knowledge of chemistry, materials, physics and mathematics.The book's coverage ranges from what polymers are and how they are structured, through their distinctive mechanical and thermal properties, to the product manufacturing processes available, and the principles of product design with them.This is the third edition of a book that has been widely used in university education of engineers and materials scientists for 36 years.It includes many new features important to the polymer engineer of today.Examples are greater emphasis on environmental concerns and how these are addressed, inclusion of bio-sourced polymers and use of natural fibres as reinforcement, and the rapidly developing 'additive manufacturing' production routes.