Al-Milal wa an-Nahal by Ash-Shahrastani (548H) - Sects & Religions

In this work "al-Milal wan-Nihal", Abu al-Fath al-Shahrastani (548H) speaks, as the title indicates, of the different religious dogmas and sects that humanity has known.

The author begins his book by talking about sects affiliated with Islam. He quotes the known sects, then for each sect the author enumerates the various (sub-sects) that are in fact drifts and branches of the main sect, mentioning their founder and explaining in detail their doctrines, their dogmatic deviations, their errors and their innovated beliefs, here are some examples:

The Mu'tazilah and their sub-sects ; The Khawarij and their sub-sects ; The Mourjia and their sub-sects ;
The Shi'ites and their sub-sects ...

Then he does exactly the same job but this time with the people of the Book and their sects:

Then again for the other polytheistic religions: Zoroastrians (majous), pagans worshipers of idols and statues, worshipers of celestial bodies, beliefs of the Arabs during the pre-Islamic period, the various polytheistic doctrines present in India, ...

He also mentions a long chapter on philosophy and philosophers (from Greek philosophy to Arabic philosophy) mentioning the founders of different currents and also explaining in detail their misguided doctrines and erroneous beliefs.