The second volume of this updated fourth edition introduces global and local non-Abelian symmetries and develops simple ideas of group theory. It covers both perturbative and non-perturbative QCD, provides an extensive discussion of spontaneously broken symmetry, and includes an application to chiral symmetry breaking and chiral perturbation theory. The text also describes weak interaction phenomenology, the GWS theory, and condensed matter (many-body) systems, including the one-dimensional Ising model, the bosonic (Bogoliubov) superfluid, and the fermionic (BCS) superconductor.