The Kitāb of Sībawayhi, compiled in the 8th century, is the oldest existant Arabic grammar. It has gone through many editions, but all are based on a copy from the 18th century.The author of this important book has discovered 11 manuscripts in addition to the 66 mentioned by F. Sezgin (GAS, IX). More than 40 were used in this book to contribute to a new understanding of the history of the text.She has now definitively shown that all of the recensions, oriental and occidental, follow closely the—now lost—copy of al-Mubarrad (d. 9th century), which functioned as a true vulgate. Only one manuscript, found in Milan, managed to escape its influence, and adhered to the rival Kufan grammatical tradition. This manuscript provides a better version of the text and makes a new reading of the Kitāb possible
