Libycus provides three top level classes, one each for access the AUTHTAB.DIR, .TXT and .IDT file of PHI/TLG disks. In general, AUTHTAB.DIR is opened by an IbycusAuthTab and used to look up an author's ID by name (e.g., Vergil = LAT0960) and this ID is then used to open an IbycusTxtFile or IbycusIdtFile.