Nova N 176 is an undeciphered manuscript codex held at the Institute of Oriental Manuscripts (IOM)  of the Russian Academy of Sciences in Saint Petersburg, Russia. The manuscript, of uncertain provenance, entered the collection of the IOM in 1954, and for more than fifty years nobody was able to identify with certainty what language or script the text of the manuscript was written in.
It was only in 2010 that IOM researcher Viacheslav Zaytsev was able to demonstrate that the manuscript is written in the Khitan large script, one of two largely undeciphered writing systems used for the now-extinct Khitan language during the 10th–12th centuries by the Khitan people, who founded the Liao Empire in north-eastern China.
The earliest known location for the manuscript was the Institute of Language, Literature and History of the Kyrgyz Branch of the Soviet Academy of Sciences. At some unknown date (1954 or earlier) the manuscript was sent from the institute in Kyrgyzstan to the Institute of Oriental Studies (IOS) in Moscow for identification and decipherment, and in November 1954, it was sent from Moscow to the Department of Oriental Manuscripts of the IOS (later the Institute of Oriental Manuscripts) in Leningrad, where it has remained ever since.
It is unknown where exactly the manuscript was found, but Kyrgyzstan is within the area of the Kara-Khitan Khanate (also known as the Western Liao), founded by Khitans after the overthrow of the Liao Empire by the Jurchens, and so Zaytsev suggests that the book probably came from a Western Liao site. Furthermore, as the Khitan script was still used by the Kara-Khitans the book may have been written during the Western Liao (1124–1218) period rather than being a relic of the Liao dynasty brought west with the fleeing Khitans. Zaytsev notes the possibility that the book may have been discovered during excavations of the Silk Road city of Suyab (modern day Ak-Beshim in Kyrgyzstan) during 1953–1954.
The manuscript was catalogued in the IOM collection as a manuscript written in the Jurchen language, and the general consensus of those few scholars who were able to examine it was that it was probably written in the Jurchen script. Despite the probable importance of this manuscript, no research on it was published until 2010, when Zaytsev presented his initial findings on the language and script of the manuscript to the annual scientific session of the IOM.
At present the precise subject matter of the manuscript is still unknown, although it appears to be different in nature to the epitaphs found on the surviving monumental inscriptions as there are significant differences in vocabulary between the manuscript and known memorial inscriptions. Due to the frequent occurrence of the Khitan characters for "state" and "emperor", Zaytsev considers that the manuscript may be a work of history or an official document
Reading the manuscript is a great challenge, as not only is the Khitan large script largely undeciphered, but the manuscript text is written in a previously unattested cursive style of writing which makes it difficult to match the characters as written in the manuscript with the forms of characters as written on monumental inscriptions. To date, only some individual Khitan characters (e.g. "state" and "emperor") and two short stretches of text that correspond to text found on monumental inscriptions in the Khitan large script have been identified and read. Zaytsev identified eight characters at the end of the 5th column of leaf 9 as meaning the date "Chongxi 14th year 2nd month", and seven characters at the start of the 6th column of the same leaf as meaning "Great Central [?] Khitan State". The characters meaning "Great Central [?] Khitan State" are exactly the same as the first seven characters on the Memorial for the Princess of Yongning Commandery (Chinese 永寧郡公主), dated 1087. The era name Chongxi is attested on various Khitan large script memorial stones, and the 14th year of the Chongxi era is the 15th year of the reign of Emperor Xingzong of Liao, corresponding to the year 1045, indicating the manuscript cannot have been written any earlier than 1045.
More information on the Wikipedia page .
An article on the manuscript can be found here .