The book begins by explaining how a comfort-driven focus has led the industry to embrace knitted fabric as a popular choice of constructional material. Using examples of leading brands, it outlines the basic terminology, structural details, and essential properties appropriate for performance apparel, especially for sportswear. This book describes the differences between woven and knitted structures, provides an understanding of fabric behavior and the characteristics of a functional garment, and outlines the importance of garment fit and consumer perception of garment comfort in its design and development.