This introductory chapter provides a detailed account of the origins of qiaopi and their significance for Chinese international migration and modern Chinese history. Emigrants’ letters and remittances home were an important link between China and Chinese overseas, who were tied—emotionally, socially, and economically—with a China in transition to a modern society and state. During the period of the qiaopi trade, from the late Qing and the Republic through to the People’s Republic, modern mechanisms and institutions of finance and communication such as banks and post offices became a cornerstone of the modern Chinese state, and the qiaopi trade in South China played a part in that process. This chapter also introduces key concepts, terminologies, and usages concerning qiaopi and qiaopi trade.