This translation of the sacred text of the Old Testament is the result of a painstaking and long-term effort, approximately thirty years, whose foundations were laid by the late professor of the Old Testament at the University of Athens and Director of the Apostolic Ministry, Vasileios Vellas. The rendering into modern Greek for the 39 books of the Old Testament, originally written in Hebrew, was done from the critical edition of the Hebrew text Biblia Hebraica Stuttgartensia, while for the books originally written in Greek, the rendering was done from the critical edition of the Septuagint (LXX) text by A. Rahlfs, "Septuaginta". The choice to translate the Hebrew text of the Old Testament was made for scientific reasons and, more importantly, to serve as the basis for the future translation of the Septuagint text, which has also been planned by the Hellenic Bible Society.