Description This volume presents an introduction to radiative transfer theory and covers the theory of scattering of isotropic and anisotropic monochromatic radiation and the theory of line radiation with complete or partial frequency redistribution. The geometry of the media considered is assumed to be a planar and infinite and semi-infinite media are studied as well as the case of a finite plane layer. The volume is intended for graduates, postgraduates and researchers in theoretical astrophysics.