The article discusses a mnvenion identity through which the series expansion of the Green's function periaining to the scalar Helmholk equation can be readily mnvened into a series expanded Green's dyadic. This expansion finds a simple application in the electromagnetic radiation theory leading to eleciric multipole and magnetic multipole terms of the vector potential and the resulting E and B fields. The dyadic is also used to obtain a series expansion of the magnetostatic vector potential. Finally, the role played by localized longitudinal and localized transverse currents in the generation of the electromagnetic field is brieEy examined, leading to the conclusion that a localized longitudinal current is self-screening. That k, it does not produce any electromagnetic fieid outside the domain of its distribution.