This chapter contains sections titled: Applications of NMR in Biology Size Limitations in Solution-State NMR Hardware Requirements for Biological NMR Sample Preparation and Water Suppression 1H Chemical Shifts of Peptides and Proteins NOE Interactions Between One Residue and the Next Residue in the Sequence Sequence-Specific Assignment Using Homonuclear 2D Spectra Medium and Long-Range NOE Correlations Calculation of 3D Structure Using NMR Restraints 15N-Labeling and 3D NMR Three-Dimensional NMR Pulse Sequences: 3D HSQC–TOCSY and 3D TOCSY–HSQC Triple-Resonance NMR on Doubly-Labeled (15N, 13C) Proteins New Techniques for Protein NMR: Residual Dipolar Couplings and Transverse Relaxation Optimized Spectroscopy (TROSY)