Book Pahlavi

Book Pahlavi is the cursive variant of the Pahlavi script, which was derived from the Aramaic script during the Sassanid period to write the Middle Persian language. Book Pahlavi was used primarily for writing books and documents, but later also for inscriptions.

Book Pahlavi is an abjad, meaning there are no unique vowel symbols, although it does make use of matres lectionis. Much like rasm in the Arabic script, a single letterform can be used for multiple letters, as they merged over time. (To avoid confusion, these are still usually transliterated differently.) Further ambiguity is added by the fact that the boundaries between letters are not clear, and many letters look identical to combinations of other letters. Like other variants of Pahlavi, many Aramaic-language heterograms (Middle Persian huzwāreš; also called "Aramaeograms") are used in Book Pahlavi texts. In transliteration, these are written as capital letters to differentiate them from Middle Persian words.

The Avestan script was derived from Book Pahlavi as a phonetic alphabet with 52 characters (including 15 vowel characters) in order to compile the traditional sacred texts of the Avesta into a book. Sometimes, Middle Persian can be written in the Avestan script, where it is referred to as Pazend.