The structure, properties, and applications of plastics are presented in this book in a way that is generally understandable yet still grounded in engineering principles. It is primarily aimed at engineers and technicians in academia and practice. The book first provides an introduction to the composition and structure of polymer materials, as far as necessary for understanding their behavior under mechanical, thermal, and chemical stress from an application-oriented perspective. Special emphasis is placed on the general mechanical properties, strength and deformation behavior, long-term behavior, residual stresses, and orientations; the effects of reinforcing agents, toughness modifications, and plasticizers are also included.