Chapter Five deals with Ibn al-Sanusi and al-Mahdi, due to their significant role. The Sanusi system is studied by examining the Zawiya and the Sufi method. The research concludes with Chapter Six, which discusses the Sanusi order. The relationship of the Sanusi order with the secular state, European states, and so forth, was covered in Chapters Two and Four. The thesis is appended with some documents that have not been published before, such as letters from Ibn al-Sanusi and al-Mahdi, selected from dozens of letters to serve as examples, and some correspondence from the governors. I am pleased to express my thanks in this introduction to everyone who helped me in this work with their suggestions and observations, including Sheikh Mansour al-Mahjoub, Sheikh of the Islamic University in El-Fashir, who allowed me to review the contents of the letters sent by Sayyidat Ibn al-Sanusi and al-Mahdi to their grandfather Sheikh, and Haj Ahmed al-Asta, an employee at the Zawiya al-Tiyamon in the National Archives, who facilitated my access to a large number of documents and translated some of them for me, and Sayyid Muhayyat al-Qara, Director of the National Archives, and Sayyid al-Tahir al-Nu'as, who showed me some manuscripts.