The miḥna or “testing” has long been considered a watershed event in an extended contest between the caliphs and the ʿulamā’ for religious authority. But was it really? Have contemporary scholars accepted a particular account of the miḥna and created a modern isnād (chain of transmission) which repeats certain assumptions about the miḥna without sufficient consideration? In this book, John Turner reassesses the miḥna and its place in the religious competition between the ʿulamāʾ and the ʿAbbasid caliphs. He begins by looking at the polemical aspects of defining someone as a heretic or a religious “other”. He then turns to accounts of heresy trials that occurred under the Umayyads and during the ʿAbbasid miḥna, which he “unpicks” to identify tropes, commonalities and the “layers” of which each account consists. Finally, he contextualizes such trials in relation to other political developments. His stated objectives are to clarify the “social role” of the caliphs with respect to religion and the normativity of caliphal involvement in heresy trials, and thus to question the assumption that the miḥna was an anomaly implemented primarily by al-Ma'mūn, and that it was a watershed event in the relationship between the caliph and the ʿulamā’.

After introducing the subject and reviewing miḥna scholarship, Turner turns in chapter 2 to the issue of heresy by exploring the objectives of doxographers in putting together volumes which defined “heresy”, i.e. beliefs outside the range of normative “orthodox” practice. As he elucidates, these works sought to define orthodoxy and thus where the line between inclusion and exclusion into the community lay, with each author claiming centrality for his religious grouping. In this sense, their aim was very similar to that of caliphs when they sought to define and prosecute heresy. Importantly, Turner's discussion flags up the fluidity of orthodoxy at this period which made the process of drawing a line between it and heresy complicated and contested by different parties, including the main players in the book itself, the caliphs, the Ashʿarites and the Hanbalis.

The next chapter compares the miḥna letters of al-Ma'mūn to Ashʿarī doxography to illustrate how the caliphs asserted their social religious role by defining and enforcing orthodoxy using similar formulae to the Ashʿarī doxographers. The purpose here is to emphasize that heretics were “those who were defined for specific reasons as being outside the community” (p. 58) and that such definitions were made by those asserting authority and normativity for themselves, whether caliphs or scholars. Chapter 4 moves to the close scrutiny of the heresy trials of two individuals, al-Ḥārith b. Saʿīd and Ghaylān al-Dimashqī, during the Umayyad period. Although the multiple accounts reviewed are late recensions, Turner manages to identify various layers within each account to make his key point that involvement in heresy trials was an expected part of a caliph's role and a facet of legitimation. However, the paucity of information about both trials does leave the reader slightly uneasy about the analysis.

Chapter 5 brings us to the miḥna itself and the trials of Aḥmad b. Hanbal and Aḥmad b. Naṣr. The miḥna provides Turner with much more material than the Umayyad cases and therefore his deconstruction of the accounts, particularly those related to Ibn Hanbal's trial, is richer and more convincing than his treatment of the Umayyad cases. It is also, of course, the trial of Ibn Hanbal which has dominated historiography about the miḥna, both Islamic and Western, because of his subsequent role as eponym of the Hanbali madhhab. Turner convincingly demonstrates that later Hanbali authors, struggling to assert their orthodoxy, had a difficult time making Ibn Hanbal into the champion of orthodoxy against an impious caliph because the earliest accounts of his trial suggested that he evaded addressing the issue at stake, the createdness or not of the Quran, or capitulated, hence his release. Conversely, Aḥmad b. Naṣr was executed during the miḥna and thus, potentially, more truly a martyr than Ibn Hanbal, creating a need for the nascent Hanbali madhhab to fit his execution into a narrative which still granted Ibn Hanbal precedence.

In the final chapter, Turner explores the deployment of heresy trials as a form of legitimation, alongside their context and timing. This enables him to show that both the Umayyad and ʿAbbasid caliphs held trials at times of crisis when it was vital to assert caliphal legitimacy and that they were often combined with other legitimating performances. Al-Maʾmūn, for instance, initiated the miḥna in conjunction with resumption of the jihād against Byzantium. This is an important corrective to the historiographical trend of seeing al-Ma'mūn's activities as anomalous and it reinforces the book's argument that both the Umayyad and early ʿAbbasid caliphs, and the Muslims over whom they ruled, considered their interventions quite normal. Moreover, it diminishes the role of al-Maʾmūn himself, who died only a few months after initiating the miḥna, and gives proper weight to the roles played by al-Muʿtaṣim and al-Wāthiq. This leads to the equally valuable insight that the caliphs only lost their religious role when they lost political power, that is with the assassination of al-Mutawakkil in 861, and that the ʿulama’’s assumption of religious authority was not so much the product of competition with the caliphs but a necessity occasioned by the demise of caliphal power itself.

In the course of his narrative, Turner successfully brings into question the pivotal nature of the miḥna and its identification with al-Maʾmūn rather than his successors. He also contextualizes the miḥna in a much longer history of heresy trials and efforts at legitimation undertaken by specific caliphs in response to their personal political circumstances, thereby offering a whole new perspective on the era. Finally, the reminder that he gives about the slow formation of the ʿulamā’ as a body and the many competing elements within that body reorients the discussion away from caliph versus ʿulamā’ to a much more varied field of interactions. This book is essential reading for anyone involved in researching or teaching this important phase of Islamic history.