Topics chosen are those of interest in astronomy, and indeed many were inspired by specific astronomical contexts. Examples include the negative ion of hydrogen and the effects of strong magnetic fields such as those occurring on certain white dwarfs and neutron stars. Adiabatic and non-adiabatic handling of electron correlations and application to processes such as dielectronic recombination are included. Astronomical examples are provided throughout, as well as end-of-the-chapter problems and exercises. Over seventy illustrative diagrams complete this unique and comprehensive volume.