The Walcausina is an eleventh-century edition of the Liber Papiensis prepared by the jurist Walcausus of Pavia (attested 1055–1079) and his school. The principal manuscripts were copied by notaries in Pavia who were contemporary with Walcausus and evidently close to his school. The text of the laws in these manuscripts reflects a conscious effort to emend the text to reflect legal practice and Latin usage. In addition to standardizing the text of the laws, the Walcausina cross-references laws dealing with the same issues, often including detailed explanations of modifications imposed by later legislation; it also provides hundreds of dialogues in direct speech that illustrate how specific laws could be invoked in court. The Walcausina also attests to the knowledge of Roman law in Pavia, mentioning all the works of the Corpus Iuris Civilis and often correlating Lombard procedures with those of the Roman law. The present edition includes more than 160 distinctions in diagrammatic form; many printed here for the first time. The appendices collect other evidence from the eleventh-century manuscripts of the Liber Papiensis and relating to the activities of Walcausus’ school.