1-Meaning.2-History.2.1-Event of Saqifa Bani Sa'ida.2.2-Conditions of Caliph.2.3-Opponents.3-Abu Bakr b. Abi Quhafa.3.1-Performance.4-Umar b. al-Khattab.4.1-Performance.4.2-Appointing the Council of Caliphate.5-Uthman b. 'Affan.5.1-Performance.5.2-Formation of Formal Ceremonies.5.3-Other characteristics.5.4-Murder of the Third Caliph.6-Ali b. Abi Talib (a).6.1-Election.6.2-Allegiance.6.3-Performance.6.4-Guidance in the Framework of the Divine Mission.6.5-Political and Economic Dimensions.6.6-Conveyance of the Prophet's (s) Intellectual and Practical Tradition.6.7-Problems of Imam 'Ali's (a) Government.7-al-Hasan b. Ali (a).7.1-Separation of Caliphate from Sultanate.7.2-Mu'awiya as the Rival of Caliphate.7.3-Compromise with Mu'awiya.8-Features of Rashidun Caliphs.8.1-Governmental Approach of Rashidun Caliphs.9-Umayyad.9.1-Mu'awiya b. Abi Sufyan.9.2-Ways of Legitimizing His Caliphate.9.3-Yazid b. Mu'awiya.10-Abd Allah b. al-Zubayr.11-Banu Marwan.11.1-Opponents.11.2-View of Khawarij.11.3-Among Muslims.12-Abbasid.13-Fatimid.14-Ottomans.15-New Approaches to the Problem of Caliphate.16-Revive of Islamic Caliphate.17-See Also.18-References.