The introduction sets out the chronological and geographical frame as well as the main issues in the study of the ancient Greek economy. It is targeted at a readership with no prior knowledge of the ancient economy and emphasises the importance of understanding economic structures, economic change, and the causes for change. As research on the ancient economy is dependent on theoretical assumptions about the nature and causation of economic change, a special section of the Companion is devoted to the discussion of the most important theoretical approaches to the ancient Greek economy. Other sections treat key themes of the ancient Greek economy, such as taxation, money, markets and labour regimes, as well as network approaches that are currently at the centre of research on ancient economies. A chronologically narrow but geographically wide perspective is taken on the Greek economy, including the Hellenistic economies in Egypt and the Near East but excluding Greek economies in the western Mediterranean and those in the eastern Mediterranean that continued to be dominated by Greek language and culture and therefore still might be termed Greek under the Roman Empire.