This study benefits gravitation, our best known and least understood phenomenon.Gravitational studies are often isolated from the mainstream of physics. This is how it should be occasionally; one needs to develop a consistent formalism per sc: but one needs also to confront it with particle physics, cosmology, astrophysics. A knowledge of cross .sections for the scattering of waves of arbitrary polarization by Schwa rzschtld and Kerr black holes contributes to the physical understanding of gravitation theory.