One of the key institutional foundations of capitalism is how creditors and debtors resolve disputes. The strictness of bankruptcy rules for large and small claims shapes how credit markets function and the extent to which they finance growth. It is, therefore, a remarkable achievement that Louise Walker traces how small-claims disputes were resolved in Mexico from the eighteenth to the twentieth century. Based on extensive archival research in Mexico and the United States, the book draws on thousands of credit conflicts to examine enforcement, the mitigation of information asymmetries, and the role of credit in shaping the lives of ordinary Mexicans between 1808 and 2008.

This book can be read as the missing link for understanding the history of church credit, nonbank lending, and modern banking over the last two centuries. Its contribution lies in tracing the evolving relationships between creditors and ordinary borrowers—largely from the perspective of debtors—thereby connecting strands of the literature often studied in isolation.

The book centers on the dyadic relationship between creditors and borrowers and traces how legal understandings of their rights evolved with shifting ideological frameworks—“be it a Roman Catholic worldview, a liberal or revolutionary perspective, or a neoliberal standpoint” (p. 8). Beyond formal law, one of its key contributions is to show how creditors and debtors developed both formal and informal mechanisms to build trust and reduce information asymmetries about borrower reputation. These evolving systems, Walker argues, reshaped everyday economic life and contributed to the emergence of an “impersonal capitalistic credit economy” (p. 8).

The narrative is organized into five chapters and a conclusion, with each chapter built around a distinct archival dataset. Chapter 1 examines small-claims disputes from the 1810s to the 1860s, showing how newly elected magistrates provided accessible adjudication, albeit with a bias toward creditor property rights. This chapter is a great narrative to understand institutional changes around creditor rights from the ancient regime to the liberal order of independent Mexico. Chapter 2 turns to the 1860s and 1870s, when creditor–debtor relations became more arm’s-length, and offers a detailed account of enforcement mechanisms, including precautionary petitions used to sequester collateral—or even individuals—prior to trial.

Chapter 3 shifts to the rise of bank credit, focusing on Banco Nacional de México (Banamex, est. 1884) and its use of R. G. Dun credit reports. Walker shows how these reports made it increasingly difficult for debtors to conceal information, facilitating the expansion of modern credit markets while also contributing to financial exclusion. Chapter 4 examines the criminalization of “bad cheques,” using an original database of arrests from the Mexico City Archive. The chapter reads in part as a business history of economic citizenship and financialization from the 1930s to the 1980s, emphasizing how stronger protections for creditors eroded debtor bargaining power.

Chapter 5 explores the rise of credit bureaus in the late twentieth century and their role in institutionalizing borrower relationships with large financial institutions, often to the detriment of debtor protections. Drawing on letters sent to President Vicente Fox (2000–2006), Walker recovers a debtor-centered perspective, showing how individuals framed their grievances in terms of long-standing notions of justice. The creation of the credit bureau in 1994, together with the 1994–1995 financial crisis, exacerbated debtor vulnerabilities and led to the emergence of new consumer protection institutions such as Condusef.

For readers familiar with the literature on the 1990s financial crisis, this last chapter is particularly illuminating. It complements a body of work largely focused on banks, bailouts, and balance-sheet indicators by foregrounding debtor experiences. More broadly, Walker succeeds in weaving a coherent narrative across two centuries of creditor–debtor relations.

The book’s most significant contribution is its breadth. Few studies trace the evolution of a core economic institution in a developing country over such a long horizon, and fewer still integrate the nineteenth, twentieth, and twenty-first centuries into a single analytical framework. The ambition to adopt a longue durée perspective makes this a compelling institutional history. Yet, because it is not a comprehensive legal history of credit relations or small-claims adjudication, some financial historians will need to look elsewhere to complement their understanding. Even so, Debts Unpaid is likely to become a foundational reference for the study of creditor–debtor relations and the enforcement of small credit claims in Mexico, as well as a valuable teaching tool for understanding how a key institutional pillar of capitalism evolves over time.