Book excerpt: Styrenic polymers are among the economically most important plastics. They combine benign processing with a large variety of product properties - from stiff and transparent to tough and durable. The fact that styrene can be polymerized by different reaction mechanisms (radical, ionic and metal catalyzed) makes this line of products unique in regards to the variety of its properties and applications. The primary objective of this book is to provide a detailed understanding of structure and property relationships of styrenic polymers, and their specific use in various applications. By understanding basic chemistry, supermolecular assembly of block- and graft polymers and microscopic fracture mechanisms, the reader will be able to quickly derive macroscopic behavior and hence select the most suitable polymer for a given application. The second objective of this book is to provide a comprehensive overview about unique value propositions of styrenic polymers in different industries and applications. The reader will get an in-depth understanding of why specific styrenic polymers dominate in market segments like computer and printer housings, exterior automotive parts and the food packaging industry, and what the specific customer benefits of using these polymers are. Finally, the third objective is to provide an outlook for future product and application developments. Hence it serves not only as a quick reference guide for downstream industries, but also as a practical guide for students and researchers in this field of material science.