Coherence and NMR places into perspective the role of quantum dynamics in NMR, addressing characterization of a system of particles with spin or any other quantum mechanical property, how such a system changes with time, and broader applications to chemistry, physics and other fields. The text also ties together the various manifestations of NMR in solids and liquids, using as a common language the unitary transformation of a system's density operator under the Hamiltonian and revealing the underpinnings of what might be called manipulative NMR - experiments in which the time-dependent SchrL+a5dinger equation is controlled externally in a non-trivial fashion.