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 proved to be adequate for studying cosmic dust, even when they must be applied to a new range of current problems. We refer, for example, to the description of mechanical interaction of electromagnetic radiation with cosmic dust grains, which is believed to be of paramount importance in determining the dynamics of the grains. Since this book is conceived as a summary of our work, the desire to encompassallnewtopicsledustorevisebothitscontentanditsstructure. Of course, beyond the changes that we outline below, all chapters were carefully revised. Marginal changes and additions were made in Chap. 1, while Chap. 2 has been substantially revised to cover the light of general polarization and, in particular, with thedescription ofthestate ofpolarization ofelectromagnetic waves of general form. In this chapter we reserved ample space for the r- resentation of the kinematics of the scattering processes both in the plane of scattering and in the meridional planes.
