Nuclear Magnetic Resonance (NMR) spectroscopy is widely used in biophysical research to study the structure, dynamics, energetics, and interactions of proteins and nucleic acids. As the power of spectrometers increase, so do the potential applications of NMR as a research tool. This book provides a clear and rigorous picture of the connection of NMR observables to biomolecular structure, motion and energetics. It illustrates important biophysical principles using both simple examples and clear pathways to more sophisticated models, and emphasizes the interconnections among seemingly independent NMR measurements based on an understanding of the fundamental chemical properties of macromolecules. This sets it aside from existing monographs and textbooks in the field which concentrate on the ways in which NMR measurements are made, and devote very little attention to how the resulting observable parameters should be interpreted. This advanced textbook is suitable for graduate level students and professional researchers using NMR as well as a wider audience of structural biologists and biophysicists.