Al-Qadi an-Nu'man القاضي النعمان or Abu Hanifa al-Nu‘man ibn Muhammad ibn Mansur ibn Ahmad ibn Hayyun al-Tamimi (died 974 CE/ 363 AH) the Isma'ili jurist and official historian of the Fatimid dynasty. Had certainly writen a lot of books and papers to defend the Fatmid dynasty and the Isma'ili and in general Shi'a jurisprudence and belief.
Arabic Wikipedia says he first was a follower of the Maliki school of fiqh. His name certainly may create confusion with that of abu Hanifa the known sunni scholar and "founder" of the hanafi maddhab.
I wonder if he actually wrote a book entitled (or maybe referred to as) "Al-Fiqh al-Akbar", if so what is the topic of this book?
Also what books did he wrote about creed and aqeedah?