The book which is the object of this study—the _Livre des Métiers_, owes its origin to a capable official of Louis IX, Étienne Boileau. He was appointed prévôt of Paris about 1260.[3] This official had the rank of the first bailiff of France. His ‘office’ was the Châtelet, where he judged in person the greater part of the civil and criminal cases in Paris and the _vicomté_; he was judge of appeal from the feudal nobles and ecclesiastics who still had fiefs in Paris. He had charge of the military service, of the policing, the finance and ‘justice’ of Paris and its suburbs. This official, or the holder of this office, “who administered with firmness and loyalty,” wished to correct the faults incident to the jurisdiction over the gilds, by establishing in writing the ‘constitution’ of each gild. The masters of the gilds accordingly presented their regulations, and the result is a register of the laws and customs of 101 craft-gilds of Paris.[4] Some of the privileges or implied immunities pretend exceeding antiquity. The stone-cutters claim immunity from the duty of the watch from the time of Charles Martel. Upholsterers cite privileges granted by Louis the VII, and the bakers claim from Philip Augustus the right to exclude ‘foreign’ bakers (i.e. bakers from outside Paris), from the markets except on Saturdays. What we have then in this invaluable _Livre_ is a cross-section of the commercial and industrial life of Paris in the third quarter of the 13th century. A study of this manuscript will show a vivid and complete picture of the working class, and, by implication, of the upper nobility’s commercial habits. The gilds were composed of three grades of individuals: apprentices, _valets_, and masters. The term _ouvrier_ was applied in general to all the divisions, even more loosely than our term _workman_. The apprentice, though considered as a member of the gild, was not of the corporation until his apprenticeship was over. The term was begun by a contract between master and aspirant. Usually this contract was oral, because the writing of a document was too expensive a process. At any rate, it was always a mutual engagement, sworn to, before the Jurés, an engagement which imposed on both parties mutual duties which neither should attempt to evade. A regulation concerning the agreement runs as follows: “The master who takes an apprentice should summon to the ceremony of the contract two masters and two _valets_, to hear the agreement made between master and apprentice, and it is fitting that the _master who guards the gild_ should be called also.” The Jurés before authorizing the contract, were supposed to make careful inquiries as to the ability and the financial position of the master.