CONTENTS 1. Introduction 743 2. Nuclear Magnetic Relaxation Without Account of Spin Diffusion 743 3. Induced Dynamic Nuclear Polarization Without Account of Spin Diffusion 746 4. Nuclear Spin Diffusion 748 5. Nuclear Magnetic Relaxation With Account of Spin Diffusion 751 6. Induced Dynamic Nuclear Polarization With Account of Spin Diffusion 758 7. Comparison of Theory with Experiment 760 8. Conclusion 762 Appendices 763 Literature 768