Abu al-Faraj Muhammad ibn Ishaq ibn Muhammad ibn Ishaq ibn al-Nadim, also known simply as Ibn al-Nadim (935-95 AD), was an Arab author, bookseller, and calligrapher. He lived in Baghdad, and briefly in Mosul, during the middle Abbasid era and, like his father, made a living from copying manuscripts for sale. Al-Fihrist, sometimes also referred to as Kitab al-fihrist (The catalog), is an index of all books written at the time in Arabic, by both Arab and non-Arab authors. It contains ten discourses. The subjects they cover are the scriptures holy to Muslims, Jews, and Christians, the hadith, history, law, biography, poetry, magic, and alchemy. The author often mentions the size of a book and the number of pages so copyists would not cheat buyers by creating shorter versions. He refers often to copies made by famous calligraphers, bibliophiles, and other libraries and describes an auction and the trade in books. The Catalog is available to the public via the Library of Congress. https://www.loc.gov/item/2021666186