Without the resources that put at your disposal techniques of the bibliography, for example, how could know the researcher, what we call the State of the problem, having access to the work of his predecessors?. I would be reduced to a dignified Penelope’s work, constantly redo work already done. How without the existence of specialized repositories, could know that there are such and which categories of documents, connected directly to which your research?. Imagine a historian who began the study of Egyptian society in the Greco-Roman era, without such support how could interact and manage the thousands of fragments of Papyri, often mutilated and dark, dispersed in collections of the? three continents and, however, constituting one of the largest sources of information?. And yet how would know that these documents exist?. And this is not more than a few thousands of document; We appreciate the importance of the historian in the presence of the colossal set pieces of all kinds, providing you with our archives modern, if not I had to guide the rules of the archives, the existence of guides, inventories, etc. Finally, the various branches of erudition, not are designed to only put documents within the reach of the historian; They also teach you the art of take advantage of them. A teacher who first browse the beautiful in-folio of the Greek inscriptions or Corpus Inscription Latinarum, even if aware of the Greek and latin, is completely disassembled front to these texts, to first view outsiders, in which stereotyped formulas, abbreviations, no sense rather than to the initiate; It is not obvious at first sight that the letters N.D.M.I designate Cybele (mother of the gods). Based on the experience accumulated by the study of thousands of inscriptions, Epigraphic discipline learns to read, to develop, eventually to rebuild, and in a Word to understand with much security, this precious category of documents.