Since the publication of the ?rst edition of this book, we have become deeply involved in astrophysics research, particularly the study of the interstellar medium. Modeling scattering particles as layered spheres or as aggregates of spherical scatterers, expanding the electromagnetic ?eld in a series of vector multipole ?elds, and resorting to the T-matrix approach for averaging over the orientations of a dispersion of nonspherical particles are e?ective tools for studying scattering theory, which we described and extensively applied in the ?rst edition of this book. In fact, these tools also...