Nuclear Magnetic Resonance (NMR) is one of the key methodology of spectroscopy, which is based on the resonation between nuclear spin and radio frequency electric wave under the strong magnetic field. Although NMR began its history as a phenomena of quantum physics, its modern pulse-FT NMR have been widely applied in the area of analytical chemistry, molecular biology, medicine and quantum computing. In this review, the basic theory of NMR is introduced according to the classical magnetization model rather than the view of quantum mechanics. The meaning of the data available from NMR, such as chemical shift, spin coupling, and coupling constant as well as basics of density matrix and product operator formalism is briefly described.
