The Costuma dAgen (customary laws of the Agenais, in south-west France) compiled in Occitan at various times in the thirteenth century and preserved in the Livre Juratoire, or swearing copy (Agen, Archives departementales de Lot-et-Garonne, MS 42), is here transcribed with an English translation on facing pages. An introduction and an index are included. Appendices provide the text of five chapters missing from this manuscript, along with several pertinent charters from Agen and a fuller description of the Livre juratoire by Professor M. Alison Stones, University of Pittsburgh. The manuscript contains many colored illustrations and capitals.The Costume emphasizes the power of the local city council, which often seems to override that of the local count. The laws or customs written in the book deal with many topics including jurisdiction, citizenship and military duties, crime, property, civil and criminal procedure, the local wine and salt trades, and local feudal law.