"Principles of Modern Physics", divided into nineteen chapters, begins with quantum ideas followed by discussions on special relativity, atomic structure and basic quantum mechanics, hydrogen atom (solution of the Schrodinger equation) and periodic table, the three statistical distributions, X-rays, physics of solids, imperfections in crystals, magnetic properties of materials, superconductivity, Zeeman, Stark and Paschen Back effects and Lasers, nuclear physics (Yukawa's theory and various nuclear models) radioactivity and nuclear reactions, nuclear fusion, fission and plasma, particle accelerators and detectors, the universe elementary particles (classification, eightfold way and quark model, standard model, fundamental interactions) and cosmic rays. New to the third edition: Bose-Einsten condensation Gamow's theory of alpha decay Fermi's theory of beta decay; gamma decay; classification of galaxies, CMBR and dark matter Hubble's constant and the future of the universe Parity violation in muon decay; fundamental particles; cosmic ray showers (types and cascade theory); nature and composition and origin of cosmic rays; effect of geomagnetic field and time variation of cosmic rays.