Basic principles of electron paramagnetic resonance -- Magnetic interaction between particles -- Isotropic hyperfine effects in EPR spectra -- Zeeman energy (g) anisotropy -- Hyperfine (A) anisotropy -- Systems with more than one unpaired electron -- Paramagnetic species in the gas phase -- Transition-group ions -- The interpretation of EPR parameters -- Relaxation times, line widths, and spin kinetic phenomena -- Non-continuous excitation of spins -- Double resonance techniques -- Other topics.