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.