Thermoplastics, being non-linear viscoelastic, impose constraints on testing which are absent in elastic and plastic materials. End products manufactured from them are often anisotropic, complicating the relationships between laboratory test data and service performance. This new book explains recently developed testing strategies for providing service-pertinent data within a limited budget. It relates the structure of the tests and the functions that they serve to the intrinsic nature of the mechanical properties of thermoplastic materials.