Kulayni's Usul al-Kafi, the theological portion of the oldest and most prestigious of the authoritative Twelver Shi'ite hadith collections, contains extensive polemics against rival Shi'ite groups, particularly the Zaydis. This text, dating from the period of the Lesser Occultation and probably containing material dating from the later Imams, demonstrates that the Shi’ite world was deeply divided during this time period over questions concerning leadership. There are several major themes relating to leadership that I have chosen to focus on in Usul a-¬kafi. These are the disputes among Shi’ites regarding the rightful successor to Imam Ali, and the ontological status of Imam, which consequently determines the basis for leadership. Shi’ites universally recognize the Prophet’s cousin and son¬-in-law, Ali, as the Prophet’s rightful successor. However, the Shi’ite religion, from the very beginning of its history has been beset with sectarian discord that left lasting effects well into the modern era. The most widely adhered to and recognized form of Shi’ism is the “Twelver” school, which recognizes the spiritual authority of twelve individuals, the “twelve Imams” as they are called, related by blood to the Prophet Muhammad. The last of these, the current Imam and rightful temporal ruler of the earth, is hidden from plain sight as a test of faith for Shi’ite Muslims. These views on the special leadership, in all of its forms is contested today by the small minorities of other Shi’ites including the followers of Zayd Ibn Ali and the followers of the various Ismaili branches of Shi’ism. These views in ages past also fiercely competed with the now defunct rival Kaysanite lineage that followed Ali’s son, Muhammad ibn Hanifiya. Of equal importance to the question of rightful leadership, is the ontological basis for said leadership. With equal zeal, Usul Al-Kafi also dedicates a great deal of itself to refuting the extremist Shi’ites who held Muhammad, Ali, or any of the Prophet’s family to be either divine or prophetic. With respect to the question between Shi’ite Islam and leadership, I have chosen to focus the issue of rebellion against an unjust ruler, the necessity of a blood relation to the Prophet’s daughter, Fatima, the ontological status of the Imam, mainly the first Imam, Ali, and the concealment of the twelfth Imam.