The fabulous wealth of the Lydian Kingdom (in what is now western Turkey) was renowned throughout the classical world—in fact, Lydia’s kings created the world’s first coinage. The Harvard–Cornell Sardis Expedition has unearthed a gold refinery from the time of King Croesus (the sixth century BC) where impure gold from the Pactolus River was treated to produce pure gold and silver. Though the ancient treasure is now gone, this volume illuminates the industry and technology that produced the riches and offers the first authoritative survey of early gold refining and assaying techniques from around the world. The authors fully describe the excavation of the only known ancient refinery and the scientific study at the British Museum to reconstruct the refining process. The unique evidence from Sardis and accounts from historical sources shed light on ancient metallurgy.