The interest in diffusion in solids is as old as physical metallurgy or materials science. It stems from application-oriented as well as from scientific reasons. First, a knowledge of diffusion is basic to an understanding of many microstructural changes that occur in solid matter at elevated temperatures. For processes like phase transformations, precipitation or dissolution of a second phase, recrystallization, oxidation, creep, annealing etc., solid state diffusion is fundamental and ubiquitous. The second reason for studying diffusion is to learn more about how atoms move in solid matter....