This volume deals with some basic considerations of structure and its relation to function. After outlining some basic principles in the first chapter, including manufacturing effects, structural determination is discussed in detail. This is important since adequate characterization in terms of molecular size is necessary for a proper understanding and suse. The theme of interrelationships between structure and properties is developed in the next chapters. The second part of the volume deals with selected applications in which the development and sue of macromolecultar materials in specific applications is described.The selection of applications includes synthetic and natural polymers and the range of medical areas involved include orthopedics, dialysis, drug release (macromolecular pharmacology) blood contact, and plastic surgery. Since the list could not be completely comprehensive, these represent areas of special development or of continuing problems.