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Nuclear Magnetic Resonance (NMR) is nowadays one of the most efficient spectroscopic techniques, providing insight into molecular structure and dynamics. The sources of the NMR Free Induction Decay (FID) signal are nuclei of non-zero spin value, precessing coherently in the magnetic field; of these nuclei, the most important and most convenient to use in biological research are 1H, 13C, 15N and 31P. The frequencies of the oscillatory FID signal are sensitive indicators of the electron surroundings of nuclei and of changes in the surroundings that are caused by inter-and intramolecular interactions. They also indicate effects such as internuclear scalar or residual dipolar couplings, which are often very subtle. The number of frequency components in the FID signal reflects the number of nuclei which are differently affected by these interactions. Since each group of such nuclei gives rise to a unique signal …