Book excerpt: This work details current advances in assessing the characteristics of polymers, single fibres and fibrous systems, and associated processes based on evolving theories in the physical, chemical and mechanical sciences. It focuses on recent develpments in selected characterization methods - such as Fourier transform infrared spectroscopy, Fourier transform nuclear magnetic resonance, electron diffraction, x-ray diffraction and electron microscopy - applicatble to polymers, fibres and textiles.