Book excerpt: Chemical reactions generally take place in solution and often involve ions. The behaviour of ions in solution, manifested through ion solvation, is therefore of prime interest in chemistry. This book considers in depth the phenomenology of ion solvation and the models and interpretations that have been proposed as the physical causes for the observed phenomena. It contains a thorough discussion of the statistical thermodynamic background of the solvation process from which a discussion of the actual thermodynamics is developed. This, in turn, serves as a background to the structural and kinetic features of ion solvation.