  We argue that the extension of the BCS theory to the strong-coupling regime
describes the high-temperature superconductivity of cuprates and the colossal
magnetoresistance (CMR) of ferromagnetic oxides if the phonon dressing of
carriers and strong attractive correlations are taken into account. The
long-range Froehlich electron-phonon interaction has been identified as the
most essential in cuprates providing "superlight" lattice polarons and
bipolarons. Here some kinetic, magnetic, and more recent thermomagnetic normal
state measurements are interpreted in the framework of the strong-coupling
theory, including the Nernst effect and normal state diamagnetism. Remarkably,
a similar strong-coupling approach offers a simple explanation of CMR in
ferromagnetic oxides. The pairing of oxygen holes into heavy bipolarons in the
paramagnetic phase and their magnetic pair-breaking in the ferromagnetic phase
account for the first-order ferromagnetic phase transition, CMR, isotope
effects, and pseudogaps in doped manganites. Here we propose an explanation of
the phase coexistence and describe the shape of resistivity of manganites near
the transition in the framework of the strong-coupling approach.
