The title is one of the series books called “The Islamic World” by John L. Esposito published by Oxford University Press, 2004 in which the unity of the Islamic world is referred to. The following is the review of the book and the quote:
Review of the book
"Even though Islam is a major religion with more than one billion followers worldwide and more than six million in the United States alone, there's still uncertainty and misunderstanding about its ideas, tenets, and practice. Understanding Islam and the people who believe in it has become crucially important in the greater world; this set seeks to foster understanding and answer questions."--Résumé de l'éditeur
“Unity of the Islamic world” in the book
Muslim leaders, however, still referred to the unity of the Islamic world and tried to present themselves as defenders of Islam rather than as rulers of specific territories.