This article focuses on Jean-Guy Belley's interest in the relationship between law and the economy—an interest illustrated by his major work on the contractual practices of the multinational company Alcan. They lament contemporary economic sociology's lack of interest—until recently—in legal phenomena, which contrasts with the close attention paid by two historic figures in “economic sociology,” Max Weber and John R. Commons, to the relationships between law and economics. The authors argue that to fully grasp the importance of the legal dimension in socio-economic analysis, we must return to the foundational insights of Weber and Commons. However, they particularly stress differences between Weber and Commons as to the unity or heterogeneity of law and the economy, the role of ethics, the search for an all-encompassing approach in the construction of ideal-types, the various forms of constraint that characterize law (whether psychological, economic, or physical), and the distinction between state law and non-state law. The latter element is why the authors, like Belley himself, argue that due consideration for legal plurality should be a central thread in any sociological analysis of the interplay between law and the economy.