Pines is a pioneer in the development and applications of nuclear magnetic resonance (NMR) spectroscopy. In his early work, he demonstrated time-reversal of dipole-dipole couplings in many-body spin systems, and introduced cross-polarization high resolution NMR of dilute spins such as carbon-13 in solids, thereby helping to launch the era of modern solid-state NMR in chemistry. He also developed the areas of multiple-quantum spectroscopy, adiabatic sech/tanh inversion pulses, zero-field NMR, double rotation and dynamic-angle spinning for quadrupolar nuclei, iterative maps for pulse sequences and quantum control, and the quantum geometric phase. His combination of optical pumping and cross-polarization made it possible to observe enhanced NMR of surfaces and the selective "lighting up" of solution NMR and magnetic resonance imaging (MRI).