The beginnings of Islam have left indelible traces in history. At that time, tremendous force and momentum led to the building of a prosperous, structured and powerful new civilization. Many authors have studied the period covering the first four caliphates, a unique historical period after the death of the Prophet. To understand Islam and analyze the history of Islamic civilization in an objective and constructive way, this book traces the main events of the pivotal period extending from the death of the Prophet to the death of the fourth caliph. It presents the life and the work of the first four caliphs: Abou Bakr as-Siddîq, 'Omar Ibn al-Khattâb, 'Othman Ibn 'Affàn and 'Alî Ibn Abî Tâlib. He recognizes in each of them an exemplary behavior and a total devotion in the direction of the affairs of the State. Abu Bakr achieved the unity of the Arabian Peninsula and organized expeditions to spread Islam. 'Omar gave a solid structure and administration to the new and expanding state. 'Othman, remained an example of integrity and tolerance. 'Ali had the heavy responsibility of keeping Muslims united. This book is the result of extensive research based on the undisputed references of Muslim authors including: Ibn Kâthir, at-Tabarî, as-Suyoûtî and Ibn Sa'd for the ancients , and al-Kindahlawî for contemporaries. The synthesis of this study gives the work clarity, precision, objectivity and exposes the historical events that generated the greatness of Islam and its apogee.