The aim of the article is to explore how Richard A. Posner began to focus on judges and courts at the turn of the 1960s and early 1970s, when his focus had previously been mostly on regulation, antitrust law, and administrative agencies. We argue that Posner's writings during this short period are critical to understanding his intellectual trajectory as they are the source of the pioneering research program that would be known as economic analysis of law a few years later. We thus emphasize the continuity between Posner's early works of the 1969-1973 period, mostly inspired by public choice theory, and his later works, and show that the former obviously paved the way for the latter.