Book excerpt: These case studies link genealogical knowledge to particular circumstances in which it was created, circulated and promoted. They stress the malleability of kinship and memory, and the interests this malleability serves. From the Prophet's family tree to the present, ideas about kinship and descent have shaped communal and national identities in Muslim societies. So an understanding of genealogy is vital to our understanding of Muslim societies, particularly with regard to the generation, preservation and manipulation of genealogical knowledge.