The 12th-century theologians working in the innovative schools of Paris and northern France taught by means of commentary on the Bible. Traditionally, teaching was primarily oral; but the later part of the century increasingly saw texts commented to parchment for wider circulation. This gave rise to a number of issues, such as how to differentiate the authoritative biblical text from the commentary, and how to differentiate commentators from one another. Fuelled at least in part by the increasing market for such school texts, a commercial and secular (as opposed to monastic) book trade began to flourish. We will look at the creative solutions the scholars came up with for presenting their material, and see how far they could be supported on the open market.