[en] A brief review of the most important features of the L-shell ionization of atoms by charged particle impact is given. It is shown that the direct Coulomb theories successfully describe the ionization processes as far as the perturbing effect of the projectile is small. For stronger perturbations induced by low velocity heavy ions, however, serious disagreement has been observed between the experimental cross section data and the theoretical predictions which indicates, among others, the failure of the hypothesis of the independent ionization of the individual atomic L sublevels. (author)