The Leningrad Codex (or Codex Leningradensis) is perhaps the oldest complete manuscript of the complete Tanach.
The Aleppo Codex (c. 930 CE), was the first notable such manuscript and is several decades older, but as noted, key parts of it have been missing since 1947, making the Leningrad Codex the oldest complete codex that has survived intact to this day. Essentially all of Jewry has integrated them both over the last millennia.
In modern times, the Leningrad Codex is most important as the Hebrew text reproduced in Biblia Hebraica (1937) and Biblia Hebraica Stuttgartensia (1977).
The Leningrad Codex, in extraordinarily pristine condition after a millennium, also provides an example of medieval Jewish art. Sixteen of the pages contain decorative geometric patterns that illuminate passages from the text. The Signature Page shows a star with the names of the scribes on the edges and a blessing written in the middle (see exhibit).
The order of the books in the Leningrad Codex follows the Tiberian textual tradition, which also matches the later tradition of Sephardic biblical manuscripts. This order for the books differs markedly from that of most printed the Tanach for the books of Ketuvim.
The Leningrad Codex (a manuscript as opposed to a scroll) is so named because it has been housed at the Russian National Library in Saint Petersburg since 1863. After the Russian Revolution scholars renamed it the “Leningrad Codex.”
[Author’s note: July 7, 2009, when I was in Leningrad, I went to the museum at 11 A.M. on a Tuesday morning (meaning, well after opening time on a regular non–Holiday weekday) and tried to view the codex. I was stopped cold. First I was told that I needed a letter from a university; then I “discussed the situation”; then I was told I might be able to pay for a special guided tour; then the Front Desk was unable to make any contact whatsoever with the department in the same main building which I was in, which oversees the codex—or its “private tours,” in any event. Everyone, including the Front Desk Manager and the apparently important Security Desk Manager—all “shrugged their shoulders.” The Leningrad Codex may just as well have been on the moon. It was inaccessible.]