The Masoretic Text is the text of the Hebrew Bible preserved meticulously by the Masoretes between the 6th and 10th centuries A.D..
To the consonantal text they added vowel points, accent marks and marginal notes thus preserving the vocalisation and pronunciation.
They were the oldest known manuscripts of the Hebrew Bible prior to the discovery of the Dead Sea Scrolls in 1947. The Dead Sea Scrolls pushed the date of the oldest known manuscripts back about 1000 years.
The Dead Sea Scrolls confirmed the accuracy of the Masoretic Text although there are some textual variants.
The main Masoretic Texts are:
Codex Cairensis
Petersburg Codex
London Codex (Oriental 4445)
Aleppo Codex
University of Michigan Torah
Damascus Pentateuch
Leningrad Codex
University of Bologna Torah Scroll
Mikraot Gedolot