This paper examines two recently published works pertaining to Mu'tazili biographical literature: the Kitab al-Maqalat of al-Ka'bi al-Balkhi (d. 319/931) and Josef van Ess’ encyclopedic Theology and Society, recently translated into English. I consider debates about the early caliphate and document the idiosyncratic political views of the Mu'tazila that disappeared with the school’s extinction. I pay special attention to theories about the legitimacy (or illegitimacy) of 'Ali b. Abi Talib (d. 40/661) as a ruler. The biographical information preserved in the works of al-Ka'bi and van Ess offers researchers a new set of lenses to understand second/eighth century debates about early Islamic history and the formation of political doctrines.