Stable Isotope Geochemistry, an introduction to the use of stable isotopes in the Earth Sciences, is subdivided into three parts: theoretical and experimental principles; fractionation mechanisms of light and heavy elements; and natural variations of geologically important reservoirs. Since publication of the 5th edition, substantial progress has been achieved in many subdisciplines of this field. Examples of these recent developments, which made a further revision necessary and are thus incorporated in the 6th edition, are: