The Sava's book (Bulgarian: Савина книга, Savina kniga; Russian: Саввина книга, Savvina kniga) is a 129-folio Cyrillic Old Church Slavonic canon evangeliary, written in the eleventh century.
The original 126 parchment folios are of Bulgarian provenience, being bound into a larger codex with later additions of the Russian Church Slavonic recension. The codex is named the priest Sav(v)a, who inscribed his name on the two of the original folios, and on who there is no other historical record and is therefore believed to be one of the manuscript copyists.
The early history of Sava's book is not known. What can be ascertained is that the codex was in the Seredkino monastery near Pskov till at least the 17th century. Afterward it was moved to the manuscript collection of the Moscow Synodal Priting House, where it was found in 1866 by the Russian Slavist Izmail Sreznevsky, who gave the codex its modern-day appellation and was the first one to publish it (Saint Petersburg, 1868). Today it's kept in the Central State Archive of Old Documents (CGADA) in Moscow.
The first critical edition of the manuscript was published by V. N. Ščepkin (Savvina kniga, Saint Petersburg 1903), photographically reprinted in Graz in 1959. Ščepkin was the first to indulge in the paleolinguistic analysis of the manuscript (Razsuždenie o jazyke Savvinoj knigy, 1899) and has ascertained that it was copied from Glagolitic original. His 1903 edition made N. Karinski to propound several new readings and fix a certain amount of wrong solutions (Perečenь važnejših netočnostei poslednego izdanija Savvinoj knigi, Izv., XIX, 3, 206-216). Paleographic and linguistic analysis shows that the copyist wrote yers there where he didn't pronounce them any more, and that behind č, ž and š he wrote ъ instead of ь, which indicates that the aforementioned consonants were pronounced "hard" in scribe's mother tongue. There is numerous evidence for the loss of epenthetic l, and instead of iotified a (ꙗ) yat (Ѣ) is often written.