It is the subtitle of this book, not its title, that serves as a guide to its contents. This book is emphatically not about Islam as understood or practiced by Muslims in German East Africa (GEA); it is about the evolution of German understandings of Islam, the extent to which Germans feared that Islam might constitute a potential threat to German colonial rule in Tanganyika and the ideas of German administrators on how best to deal with Islam and Muslims in the protectorate. Through a careful reading of colonial and missionary archives, parliamentary debates and periodicals of the period, Haustein deconstructs German ideas about Islam, Arabs and Black Africans, describing how administrators recycled tropes that served to justify particular policies. Far from depicting German attitudes and policies as a unity, the book showcases differences between politics and attitudes in Berlin and GEA, differences between the perspectives of colonial administrators and missionaries and the ways that the rhetoric that each group used varied according to the political needs of the moment. In addition to consulting German sources, Haustein analyses the few Arabic and Swahili texts preserved in the colonial archive.

The book begins with a helpful historical introduction of GEA and a survey of the existing literature. Throughout the book, Haustein clearly explains the political contexts for the issuance of diverse and changing arguments and opinions on Arabs, Black Africans, Islam, the Swahili language, administrative policy and other topics, offering new information and fresh insights that make this book a worthy contribution to scholarship.

Haustein chronicles the mainstreaming of the narrative of ‘Islamic danger’, in contrast to an earlier narrative of East African Islam's docility, and notes that scholars also jumped on the bandwagon, ‘keen to inject their expertise into the public debate, and even where they did not agree with the alarmism of missionary advocacy and press reports, they sought to reap the benefits of the rising uncertainty about Islam for positioning their subject’ (p. 306). One might note a more recent parallel phenomenon: after the 9/11 attacks, public perceptions of Islam's danger created new academic positions in Islamic thought; even those who do not agree with this perception take advantage of the opportunities it creates. Haustein's critical exposé of the writings and politics of the two most important German Islamicists of the time, Eduard Sachau and Carl Heinrich Becker, will interest scholars for whom Sachau and Becker's works continue to be important references. He concludes that ‘the Germans were fooled by the ghosts of “Pan-Islam” that their insular debates of Muslim “danger” had conjured up. What they encountered in the colony was a much more hybrid, complex, and fleeting presence than the political subject of “Mohammedanism” they imagined to be confronting’ (p. 346).

Regrettably, Haustein does not adequately explain this complexity, beyond noting the presence of diverse ethnic groups and sects among the Muslim population. How different were they in reality? To what extent did they interact? These questions are ignored. Likewise, he notes that Muslim leaders could exploit German anxieties in order to settle scores, ‘as long as their religious rivals could be presented as “religiously seditious”’ (p. 304, cf. p. 348), but provides no examples of this actually occurring.

The text has a number of typographical errors, omissions of words and occasional errors of wording (e.g. ‘contented’ instead of ‘contended’, p. 235). Some of the wording strikes this native speaker as odd, such as the use of ‘tact’ in a context that implies its opposite (p. 301). Most grating is the use of ‘elision’ to mean ‘omission’ in a more general sense than its standard usage, specifically the systematic ‘elision’ of Islamic thought and practices from the body of ‘native law’ in GEA. Haustein links this to Carl Heinrich Becker's insistence on local context rather than the universality of Islamic law. While he rightly notes that Becker had never been to GEA and had no basis for his assumption that Islamic law was rarely followed there, the implied criticism of Becker's insistence on the primacy of ‘lived Islam’ instead of literary Islam is unexplained and contradicts the current pushback against Orientalist ‘essentialising’ of Islam. It is true that anthropologists and historians have sometimes insisted on the ‘African’ character of Islam in Africa, contrasting it with ‘Arab Islam’, failing to realise that there is no single ‘Arab Islam’ and that these ‘African’ features may be found throughout the Muslim world. But Haustein's point is unclear: what, exactly, is wrong with Becker's insistence on knowing not only what books were found in a scholarly library in GEA, but the extent to which they were used in the local context? Nonetheless, Haustein is right to criticise Becker's assumption about the representativeness of the confiscated documents at his disposal, as well as Becker and Sachau's dismissal of local fiqh scholarship, failing to ‘even entertain the possibility of cosmopolitan scholarly erudition in the East African “periphery”’ (p. 248).

Haustein makes good use of the few Arabic and Swahili sources at his disposal, but there are numerous errors in the transliteration of Arabic names and words. In the last chapter, he critiques Sebastian Gottschalk's Kolonialismus und Islam: Deutsche und britische Herrschaft in Westafrika (Frankfurt, 2017) for failing to include ‘Islamic actors’. But that is precisely the problem with Haustein's own book. He points out the impossibility of representing local identities and concepts by using the archival record, and there is a paucity of indigenous primary sources, particularly Arabic and Swahili written texts that reflect the lived context. This is his justification for relying on European sources. Haustein argues that the post-colonial historian's task ‘cannot be to write a history of “lived Islam” under colonial rule’, but only to reconstruct the genealogy of European representations of Islam (p. 355). This is a disappointing, though perhaps inevitable, conclusion. One can only hope that the work of scholars such as R. S. O'Fahey, Anne K. Bang, Ridder H. Samsom, Kai Kresse and others will help historians access indigenous sources that might offer a different perspective.

Haustein reminds us that ‘the very idea of Islamic Studies emerged within the context of Germany's colonial endeavours and resonated because of its political utility’ (p. 366). This deconstruction of influential and enduring tropes serves as a cautionary tale and a call to interrogate the assumptions we bring to scholarship. He believes that the goal of the study of Islam is ‘not to determine the past, but to enable a fuller present’ (p. 369). A worthy goal, to be sure, but it is to be hoped that historians will not renounce the ongoing effort to understand the past, and not only from the vantage point of biased imperialists.