This volume contains the edited versions of some selected lectures delivered at the famous "Schladming Winter School," devoted to "Flavor Physics" in the present case. Flavor physics is one of the hot topics in contemporary elementary particle physics, because it relates to fundamental questions like the origin of masses, the size and strength of CP violation and the oscillations between various neutrino species. This volume will be useful for graduate students wishing to get more acquainted with fhe field as well as for lecturers in search of material for seminars of special lectures and courses in quantum field theory.