When did milk become part of human diet and how did its arrival influence the emergence of cities and civilisation? Archaeologists and chemists are examining ceramics and pottery shards from the Ashmolean Museum in Oxford and finding milk residues that are thousands of years old. Quentin Cooperfinds out how analysing these remains can tell us when humans first became dairy farmers and what it mighttell us about the evolution of lactose tolerance and modern Civilisation. Producer Pamela Rutherford