We shall review the basics of the McKay correspondence in 3 dimensions, which allows one to understand the geometry of the crepant resolutions of quotients C3/G, where G is a finite subgroup of SL(3,C), just by studying the group G. We shall also discuss the construction of the resolutions of singularities by means of moment maps and Kähler quotients, highlighting how all geometric objects involved have a precise interpretation as ingredients of a field theory (D=3 N=2 Chern-Simons gauge theory).