With a few exceptions, there is a noticeable dearth of scholarly literature on the introduction of Sufism into Yemen and its development during the medieval period. Muhammad Ali Aziz's in-depth study of one of the leading Sufis of medieval Yemen is a welcome addition to a field in which there is increasing interest: the development of Sufism in regions beyond the central lands of Iraq and Persia. As the cover of this book rightfully states, this is “the first study of Ibn ʿAlwān and the first comprehensive analysis of medieval Yemeni mysticism in Western scholarship”.

Aḥmad b. ʿAlwān (600/1203–665/1266) lived to see Yemen's transition from Ayyūbid to Rasūlid rule, an event he probably witnessed personally due to his father's position as a royal scribe to the region's last Ayyūbid ruler. As the author has shown, Ibn ʿAlwān left a lasting impression in Yemeni religious life due to both his charismatic persona as a mystic saint, and as a prolific writer of theological-mystical works. In addition, he has earned a position in the narrative of modern Yemeni nationalism as one of the nation's foremost poets (his mystical odes are still recited in the daily liturgies of many of Yemen's Sufi orders), and some modern Yemeni commentators have drawn inspiration from his image as a pre-modern champion of the oppressed (based on lines of poetry in which he criticized the Rasūlids, see pp. 57–9). Despite Ibn ʿAlwān's criticism of the new ruling dynasty, the author makes it clear that through a combination of patronage, stability and the creation of the right socio-economic conditions, the Rasūlids oversaw a golden age of Sufism in Yemen, producing many influential mystics including Ibn ʿAlwān himself.

Of the nine chapters, only four (3–6) focus on Ibn ʿAlwān and his writings. These cover a wide variety of topics related to the study of Sufi thought and practice, although the study's focus on theological matters can be seen as part of a growing interest, displayed in a number of recent studies, in the relationship between Sufism and Islamic theology and doctrine. Although the biographical section of chapter 3 does not provide us with much information concerning Ibn ʿAlwān's teachers and intellectual formation, the title and subject matter of one of his major works, al-Tawḥīd al-Aʿẓam (translated by the author as “The Divine Union”) underlines the importance of understanding the theological dimension of his teachings. However, despite the declared promise in the book's title of an exploration of this subject, the treatment of theological issues is fairly minimal and rarely goes beyond comparing the positions Ibn ʿAlwān took on a number of basic question with those of the major theological schools (which are often presented in a rather monolithic manner). One exception is the section on Ibn ʿAlwān's apparently Shii views (pp. 85–9). His interesting attempt to formulate a compromise on this question along Sufi lines (by teaching that Abū Bakr and ʿAlī had equal claims to leadership due to their separate roles as the respective “poles” of the physical and spiritual realms) reflects the continued significance of the Sunni–Shii conflict in Yemen long after the fall of the Fāṭimid Caliphate in Egypt. For the most part, it seems that the author is keen to present the subject of his study as a mainstream Sunni in matters of doctrine and law. The book frequently reiterates that Ibn ʿAlwān was an adherent of “moderate Sufism”, but nowhere is this category explained or justified clearly. Basing one's mystical teachings on the proofs of the texts of the Quran and prophetic narrations was fairly commonplace among the various shades of Sufism, even those perceived by many as “heterodox”, and therefore not a sufficient argument in favour of a Sufi's “moderateness”. Although Ibn ʿAlwān appears to have taken the position that one who is sufficiently learned in the key religious sources (i.e. the Quran and the prophetic Sunna) can dispense with the need for a guiding master (shaykh) in order to pursue the Sufi path, his general views on the relationship between masters and disciples does not seem to give the Sufi master a lesser role than that found in the teachings of other Sufis, and one wonders to what degree his justification of the practice of kissing a master's feet (p. 116) might have sat well with many non-Sufi jurists. The book's discussion of the controversy between Sufis and jurists over the question of sainthood, explored in chapter 7, shows us that central questions on the relationship between Sufism, Islamic theology and law were far from settled long after Ibn ʿAlwān's time.

On the whole, however, this book does a commendable job in summarizing Ibn ʿAlwān's mystical teachings and comparing them with the teachings of other major exponents of Sufism. In particular, the sections discussing Ibn ʿAlwān's poetry are gripping, and reflect the author's strong grasp of Arabic in both its classical and colloquial Yemeni forms. One also has to commend the author's ability to draw on a vast amount of secondary material, including the research of contemporary Yemeni scholars, which may not always be within the reach of foreign scholarship. For both general and specialist readers, the real strength of this book lies in the chapters that deal with the broader issues relating to the history of Sufism in Yemen. Chapters 1 and 2 discuss more general aspects of Yemen's history, including the development of the major religious sects in the region. Chapter 7 promises a discussion of the manner in which an image of Ibn ʿAlwān as a popular saint developed, but actually focuses mainly on the more general controversy among scholars of Yemen over saint veneration and the practice of visiting tombs of saintly figures. Chapters 8 and 9 also touch on wider issues, namely the relationship between Sufis in Yemen and their main rivals, the Zaydi Shii imams and Sunni jurists. In chapter 9, one also finds a useful summary of the history and unique characteristics of each of the major Sufi orders (turuq) in Yemen.

Owing to the pioneering nature of such a study, and the lack of much foundational research upon which it could have been based, it is understandable that it comes across as rather dense. In a more developed field of research, the author might have been able to forgo the detailed introductory discussions on the history of Islam and Sufism, and focus more on the subject of Ibn ʿAlwān and his teachings. However, these introductory discussions bring much welcome new material to the field. Despite its density, the author has also managed to present his arguments in a clear and systematic manner. However, one occasionally comes across discussions of the finer aspects of Ibn ʿAlwān's teachings that deserve more detailed treatment, such as his idea that one could experience both the Sufi states of annihilation (fanā’) and remaining (baqā’) at the same time (see p. 131), or the way in which he interpreted certain Quranic verses in a way that avoided anthropomorphizing God (pp. 127–8).

Overall, despite the limitations in its treatment of theological matters, and the occasional lapse of scholarly tone into the language of Muslim piety (see examples on pp. 128, 192, 200, 206), this is an engaging and well-presented work on the history of Sufism in a country that is often neglected by modern scholars. Recent events make it easy to forget that Yemen has not always been a land renowned for terrorism and instability. It is hoped that the author continues to provides modern scholarship with interesting glimpses into Yemen's rich and colourful past, and the central role Sufism had in its cultural formation since the “golden age” of the Rasūlids.