Patchwork, same-sex marriage, in vitro fertilization - what some call the decline of the West is for others an expansion of our concepts of love, relationships, and family. Christina von Braun, one of the country's most renowned cultural scientists, looks far back into history to explain how our ideas of kinship have developed. Her new foundational work will change our perspective on the present. "Blood is a very special juice," says Mephisto to Faust, whom he makes sign the pact with his blood. For Western culture, "blood ties" are also the basis of kinship. This is not the case for all cultures. In her new standard work, Christina von Braun demonstrates the ideas on which the concept of blood kinship is based and how these ideas are changing in the age of genetics and reproductive medicine.