Book excerpt: ‘‘Biopolymers’’ are polymeric materials of biological origin, including globular, membrane, and fibrous proteins, polypeptides, nucleic acids, po- saccharides, lipids, etc. and their assembly, although preference to respe- ive subjects may be different among readers who are more interested in their biological significance or industrial and/or medical applications. Nevert- less, characterizing or revealing their secondary structure and dynamics may be an equally very important and useful issue for both kinds of readers. Special interest in revealing the 3D structure of globular proteins, nucleic acids, and peptides was aroused in relation to the currently active Structural Biology. X-ray crystallography and multidimensional solution NMR sp- troscopy have proved to be the standard and indispensable means for this purpose. There remain, however, several limitations to this end, if one intends to expand its scope further. This is because these approaches are not always straightforward to characterize fibrous or membrane proteins owing to extreme difficulty in crystallization in the former, and insufficient spectral resolution due to sparing solubility or increased effective molecular mass in the presence of surrounding lipid bilayers in the latter.