Presocratics Source presents the transcription of the famous collection of Presocratic thinkers in ninety chapters originally edited by H. Diels and W. Kranz (Die Fragmente der Vorsokratiker, ed. by H. Diels-W. Kranz, 3 vols., Weidmann, Berlin, 19582), with the parallel Italian translation edited by G. Giannantoni (I Presocratici. Testimonianze e frammenti, a cura di G. Giannantoni, Laterza, Roma-Bari, 19832).Presocratics Source enable users to access texts, exploit resources, and perform queries. Notes, additional information and a legenda for a better access to the text are also available.The publication is peer-reviewed and aspire to meet the highest quality standards. The content of the site and its internet addresses are stable and can be freely consulted and used for scholarly purposes. The site will be soon open for semantically enrich the data published on the websites. A use of peer-to-peer (p2p) networking will also provide an efficient and engaging collaborative work space.