The corpus of Paulus' Libri Singulares occupies a very special position within the jurist's production. They may be united by their specific layout in a single volume although their content is quite varied, spanning all areas of public, private and procedural law, albeit generally monographic in nature. It is precisely that format, in addition to the surprisingly large number of titles handed down to us, that fuels suspicions about the real Pauline authorship of many of them. The problems of authorship of the books and the materials included in them therefore represent a further field of investigation for the contemporary scholar. The first volume analyses, through the exegetical sifting of the relevant fragments, 13 writings selected on the basis of thematic criteria: those pertaining to judicial mechanisms (from the civil to the criminal sphere, and from the formular trials and 'per quaestiones' to the 'cognitio extra ordinem'), those on substantive criminal law (and in particular on the punishments for various crimes), and finally, straddling the line between judiciary functions and public law, those on commentary and instruction for various imperial officials (with the inclusion of works on the management of the 'tutelae'.