About “Al-Milal wa al-Nihal”
Kitab al-Milal wa al-Nihal, written by the Islamic scholar Muhammad al-Shahrastani around 1127-1128, is a non-polemical study of religious communities and philosophies existing up to his time, considered the first systematic study of religion. It divides religions between sects with written doctrines and creeds and those without. (Summary adapted from Wikipedia, CC BY-SA 4.0.)
Some summaries adapted from Wikipedia, CC BY-SA 4.0.