The Nation or the Ummah: Islamism and Turkish Foreign Policy
The title is a book by Birol Başkan, Ömer Taşpınar, published by State University of New York Press, 2021. In the book, there is a note about the unity of the Islamic world. The following is a review about the book and the note.
Review of the book
Turkey's enthusiastic embrace of the Arab Spring set in motion a dynamic that fundamentally altered its relations with the United States, Russia, Qatar, Egypt, Saudi Arabia, the United Arab Emirates, and Iran, and transformed Turkey from a soft power to a hard power in the tangled geopolitics of the Middle East. Birol Başkan and Ömer Taşpınar argue that the ruling Justice and Development Party's (AKP) Islamist background played a significant role in the country's decision to embrace the uprisings and the subsequent foreign policy direction the country has pursued. They demonstrate that religious ideology is endogenous to—shaping and in turn being shaped by—Turkey's various engagements in the Middle East. The Nation or the Ummah emphasizes that while Islamist religious ideology does not provide specific policy prescriptions, it does shape the way the ruling elite sees and interprets the context and the structural boundaries they operate within. 
“Unity of the Islamic world” in the book
Having realized the futility of military invasion in subduing and destroying the unity of the Islamic world, the West adopted a new approach and as a part of it spread the idea of ethnic nationalism among Muslims.