A general method is provided for constructing Jones's reflection and transmission matrices of any beam splitter. Derivations are presented for the various known configurations. The method uses Abelès's matrices and pays special consideration to the different expressions of Jones's matrices relative to the various beams in an interferometric arrangement. The reversibility of the beam splitter in its action on the amplitude or phase, or both, of an incident light is studied. It is finally suggested that, even for an asymmetric beam splitter configuration, the symmetry of the interferogram can still be preserved by adjusting the thickness of the beam splitter in a prescribed manner.