This book places the troubles of ordinary people at the centre of economic change in Mexico, arguing that conflicts over small-scale unpaid debts were a stress test for the economic and political order. Studying malfunction – what happened when contracts broke or soured – exposes the ways in which debt trouble became a driving force in the history of accumulation and justice in the modern world. This concluding chapter offers final thoughts on the book’s core proposal: that a broad sense of fairness and justice provided a bedrock of stability that allowed for massive economic transformation over a long chronological horizon.