The authors of this book present current research in the study of superconductivity. Topics discussed in this compilation include the effects of non-magnetic defects in hole doped cuprates, deep cryogenic refrigeration by photons based on the phonon deficit effect in superconductors, superconductivity driven by an anti-polar electric phase in high temperature superconducting materials, superconductive graphite intercalation compounds, a superconducting magnetic field concentrator with nanodimensional branches and slits, magnetic mechanisms of pairing in a strongly correlated electron system of copper oxides, two non-linear mechanisms of correlations between copper carriers in superconductivity and their microscopical descriptions, three dimensionality of the critical state and variational methods for magnetically anisotropic superconductors, theory of multi-band superconductivity, conserving approximation for the self-energy of the t-U-V-J model beyond the Hartree-Fock approximation, and superconductivity as a consequence of an ordering of zero-point oscillations in electron gas.