In collaboration with colleagues in physics and metallurgy, Cécile Morrison has helped transform our knowledge of the techniques of late Roman and Byzantine coin production. The results are illustrated in the studies here which look in detail at standards of refining and processes of debasement. This analysis can also identify sources of metal, and explains the enigmatic appearance of concave gold coins n the 11th century. The volume itself opens with a comparison of the methods of numismatics and sigillography, and an epigraphic study showing the conservatism of the Byzantine coinage up until 1204. The following articles turn to the finances and economy of Byzantium, making full use of recent advances in numismatics. They aim to assess the importance of the state and other economic agents during the empire's different phases of expansion and contraction, and demonstrate how fiscal documents and legislation on treasure hoards can be used as evidence for the state of public finances.