We summarize the main features and results of the magnetic resonance experiments on small particles. The spin-orbit coupling in the metal determines the electronic g-shift and hence the electron spin relaxation time and the spin depairing parameter, /τƊ, where τ is the spin relaxation time and Ɗ is the average electronic level spacing. The depairing parameter governs the applicable statistics for the small particle system ; the electronic susceptibility in even particles in the ground state ; and the width of C.E.S.R. line when the spin relaxation mechanism is quenched. In the last circumstance the hyperfine broadening should be predominant in pure metals. Interaction of the conduction electron spins with spins in the embedding matrix at the particle surfaces produces broadening of the C.E.S.R. The N.M.R. shift in even particles reflects the electron nuclear hyperfine interaction and the electronic susceptibility, and hence the depairing parameter. The N.M.R. width is usually dominated by interactions with matrix impurities in analogy to the C.E.S.R. width. Values of the depairing parameter derived from residual N.M.R. shift give an indirect measurement of electron spin relaxation time