The article by A.I. Buzdin discusses the unique characteristics of the proximity effect in superconductor-ferromagnet (S/F) systems, where the Cooper pair wave function in the ferromagnet exhibits damped oscillatory behavior. This behavior is analogous to the inhomogeneous superconductivity predicted by Larkin and Ovchinnikov and Fulde and Ferrell. The author provides a unified description of the properties of S/F heterostructures, focusing on the non-monotonous dependence of the critical temperature of multilayers and bilayers on the ferromagnetic layer thickness and the conditions for "π"-Josephson junctions. Recent progress in high-quality hybrid systems has allowed for the observation of various interesting effects, such as domain-wall superconductivity and the influence of superconductivity on the magnetic structure in S/F bilayers. The article also covers the paramagnetic limit, the exchange field in ferromagnets, the Fulde-Ferrell-Larkin-Ovchinnikov state, and the generalized Ginzburg-Landau functional. Additionally, it discusses the damped oscillatory dependence of the Cooper pair wave function in ferromagnets, density of states oscillations, Andreev reflection at the S/F interface, and the spin effects in Andreev reflection. The author concludes by analyzing the phenomenon of domain-wall superconductivity and the impact of superconductivity on ferromagnetic order in S/F bilayers.The article by A.I. Buzdin discusses the unique characteristics of the proximity effect in superconductor-ferromagnet (S/F) systems, where the Cooper pair wave function in the ferromagnet exhibits damped oscillatory behavior. This behavior is analogous to the inhomogeneous superconductivity predicted by Larkin and Ovchinnikov and Fulde and Ferrell. The author provides a unified description of the properties of S/F heterostructures, focusing on the non-monotonous dependence of the critical temperature of multilayers and bilayers on the ferromagnetic layer thickness and the conditions for "π"-Josephson junctions. Recent progress in high-quality hybrid systems has allowed for the observation of various interesting effects, such as domain-wall superconductivity and the influence of superconductivity on the magnetic structure in S/F bilayers. The article also covers the paramagnetic limit, the exchange field in ferromagnets, the Fulde-Ferrell-Larkin-Ovchinnikov state, and the generalized Ginzburg-Landau functional. Additionally, it discusses the damped oscillatory dependence of the Cooper pair wave function in ferromagnets, density of states oscillations, Andreev reflection at the S/F interface, and the spin effects in Andreev reflection. The author concludes by analyzing the phenomenon of domain-wall superconductivity and the impact of superconductivity on ferromagnetic order in S/F bilayers.