This codex (designated as B 19^A) is the oldest known complete Hebrew manuscript of the Hebrew Scriptures (or, Old Testament). The codex contains the Masoretic text, which was copied in Al-Fustāt (Old Cairo), Egypt, in 1008/1009 C.E. (See MASORETIC TEXT.) It is preserved in the Russian National Library in St. Petersburg (formerly Leningrad), Russia.

The codex comprises 491 leaves of thick, white parchment, each measuring 30 by 27 cm (12 by 11 in.). The text is written in three columns per page except in the poetic books of Job, Psalms, and Proverbs, where it is set out in two columns per page.

The Leningrad Codex was produced by the scribe Samuel ben Jacob. He used several manuscripts prepared by the renowned Jewish scholar Aaron ben Asher, who had examined all the available contemporary Hebrew Scripture manuscripts with the goal of reconstructing a text as close as possible to the original. This codex provides the base text for recent scholarly editions of Biblia Hebraica, the Hebrew text on which most modern Bible translations are based.​—See BIBLIA HEBRAICA.

The Hebrew Bible text in the Leningrad Codex is remarkably consistent with that found in many of the Dead Sea Scrolls, which are more than 1,000 years older. (See DEAD SEA SCROLLS.) While there are some variations in wording, the message remains the same.​—See App. A3.