A comprehensive collection of papers on theoretical aspects of electronic processes in simple and synthetic metals, superconductors, bulk and low-dimensional semiconductors under extreme conditions, such as high magnetic and electric fields, low and ultra-low temperatures. The main emphasis is on low-dimensional conductors and superconductors, where correlated electrons, interacting with magnetic or nonmagnetic impurities, phonons, photons, or nuclear spins, result in a variety of new physical phenomena, such as quantum oscillations in the superconducting state, Condon instability, Skyrmions and composite fermions in quantum Hall effect systems, and hyperfine field-induced mesoscopic and nanoscopic phenomena. Several new experimental achievements are reported that promise to delineate future trends in low temperature and high magnetic field physics, including the experimental observation of the interplay between superconductivity and nuclear spin ordering at ultra-low temperatures, new observations of Condon domains in normal metals, and an experimental proposal for the realisation of isotopically engineered, semiconductor-based spin-qubit elements for future quantum computation and communication technology. weiterlesen