<DIV></DIV>This book represents a system of theoretically derived inherent laws of fibrous assemblies and looks specifically at yarns, paticularly from a structural point of view. Each chapter starts with definitions, terminologies and fundamental relations. The first part of the book presents the theoretical models of structure and mechanics from initial assumptions through the mathematical derivation to the final relations. Problems such as packing, density, porosity, pores, fiber orientation, tensile behavior of bundles and multiaxial systems, fibre–to–fibre contacts and compression of fibrous assemblies are also discussed in the second part of the book. Chapters in the final part of the book look at the structure and mechanics of yarns, focusing on yarn count, twist and diameter, number of fibers in cross-section, retraction and saturated twist, fiber migration, unevenness, hairiness, tensile behavior, and shrinkage.