‘You are what you eat … plus a few per mil’ explains delta notation and organic isotopic fractionation. An isotopic balance has to be maintained, so the isotopic fractionation into a mineral crystallizing from a fluid will be balanced by a change in the isotopic composition of the remaining fluid. Carbon, nitrogen, oxygen, and strontium isotope values can be measured through the food chain and in animal and human bones. There is also a geographical oxygen isotope zonation, but this is disrupted by major changes in topography. Isotopic measurements helped in identifying King Richard III’s bones and providing background to the life of the 5,000-year-old ‘Ötzi the Iceman’ found in the Ötztal Alps.