  This paper overviews various phenomena related to the concept of isospin
symmetry. The focus is on N~Z nuclei, which are excellent laboratories of
isospin physics. The theoretical framework applied is nuclear Density
Functional Theory and its isospin- and angular-momentum projected extensions,
as well as symmetry-projected multi-reference models. The topics covered
include: isospin impurities, superallowed beta decays, beta-transitions in
mirror nuclei, isospin breaking hadronic interactions, mirror and triplet
binding energy differences, and isoscalar pairing.
