The last century of the Ottoman Empire, known as the empire's longest, continues to be the most contested, studied, and debated period of its history. Focusing on apostasy and religious conversion in the late Ottoman Empire, Selim Deringil situates the ways in which confessional affiliation was turned from fluid communal belongings into tight markers of ethno-national affiliation. Through an in-depth historical study of the Ottoman Balkan and Anatolian provinces, Deringil takes social and structural changes of the empire in the nineteenth century as an entry point for understanding conversion and ethno-sectarian tensions. The events central to this book—the expansion of Western European colonial empires, the spread of nationalism in the Ottoman Balkans, and the Ottoman state's structural changes—are all necessary background to situating conflicts in late and post-Ottoman societies.

Unlike religious conversion prior to the nineteenth century, conversion out of one's confession now meant rejection and withdrawal from one's national identity. This is why Deringil regards confessional conversion as a process of denationalization of communities and individuals, which he defines as the “loss of a soul and a body from an increasingly ‘nationally imagined’ community” (3). While many scholars have challenged the proposition that secular nationalism would replace “primordial” attachments, this study demonstrates the centrality of confessional belongings in forging communal identities and polities in an imperial setting. It eloquently demonstrates that this process was intrinsic to both the modernization of the Ottoman state and the emergence of nationalist movements in the Balkans. An appealing feature of the book is how Deringil weaves structural changes in the imperial state together with the daily lives of ordinary people in different provincial settings.

The book spans the structural changes that took place between the Tanzimat Edit of 1839 and the end of Sultan Abdülhamid’ reign in 1909; it stops just about when the Young Turk regime became the de facto ruler of the Ottoman State. The reforms that took place between 1839 edict and the 1876 constitution led to the rise of a new order of the “Tanzimat State.” This imperial order sought to establish new ways of consolidating the state's legitimacy by mobilizing and managing its populations (ch. 1). The conversion out of Islam became permissible and the conversion into Islam was bureaucratized and discouraged because of its political ramifications for the Ottoman state due to diplomatic pressures exerted by European powers (ch. 2). For the Tanzimat State, Deringil says, conversion and apostasy were considered an “imperial headache” to avoid and he provides many conversion cases to support his argument. That of a Bulgarian girl's conversion to Islam in Salonika is a succinct account of how a single case of conversion could lead to communal and diplomatic crisis for the state (ch. 2).

The granting of religious freedom by the Tanzimat State had further consequences for the Ottoman state and society such as the emergence of a population of hidden or crypto-Christians (ch. 3), as well as the conversion of “career converts” for social and economic benefits (ch. 4). But this order was short-lived; Deringil marks the reign of Sultan Abdülhamid (r. 1876–1909) as the end to the Tanzimat State, particularly because the Hamidian State did not practice equality between Muslims and non-Muslims. The changes in how the Hamidian State dealt with the mass conversion of Armenians in the wake of the massacres of the 1890s marks the beginning of the state's reliance on its Muslim population for loyalty and legitimacy (ch. 5). The assumption was that Armenians could make autonomy claims in Anatolia and threaten the empire's heartland, similar to what happened in the Balkan provinces.

Deringil's account of the Islamization of the Ottoman sheds new light on the beginnings of the Republic of Turkey and the ways in which it was imagined as a “secular” nation-state with affiliation to Sunni-Islam as an ethnic marker for its citizens. This becomes an important context for the contested history of the Ottoman Armenian population in contemporary Turkey. For this reason, Deringil reminds us that the Hamadian massacres should not be confused with the genocidal policies of the Young Turk regime, which ruled the empire and later republican Turkey between 1908 and 1950, according to the periodization of Erik Zürcher in Turkey: A Modern History.

Deringil is a historian who does not lose sight of contemporary politics when he writes about the past. He demonstrates the ways in which the ethno-sectarian nationalist order of the nineteenth century unraveled in the post-imperial nationalist polities in the Balkans and the Middle East. This study is thus crucial for scholars who study states, societies, and conflicts in (post)-Ottoman societies and beyond. The approach Deringil employs is methodologically important since it broaches the isolation between the Balkans and the Middle East, as geopolitically separate. It is notable that both regions were one contiguous space for most of their histories due to imperial invasions and movements of people, ideas, and goods. Scholars of the late and post-Ottoman periods cannot ignore the importance of the rise of national identity, with Orthodox Christianity as an ethnic marker, to the policies of Islamization and the subsequent mass annihilation of Armenians from their native Anatolia. This approach also challenges the insular assumptions in area studies by providing contextualized historical studies that open new venues in which to map the ruptures, as well as continuities, in post-imperial and postcolonial states and societies.