The present monograph derives from the author's thesis (Åbo 2008) and differs from it merely in the disposition of material. Right from the outset it is worth stressing that this is the first comprehensive study of the ascetic doctrine of one of the best-known representatives of Syriac Christianity (sharing this fame with Ephrem of Nisibis). Isaac's works not only circulated in the different branches of Syriac Christianity (East Syrian, West Syrian, Rum Orthodox, Maronite) but were also translated, from the Middle Ages onwards, into various languages. They are available today even in Japanese.

Isaac's works exerted a profound impact on the Christian world – although only the ‘first part’ of his corpus, edited by P. Bedjan in 1909, enjoyed universal popularity, whereas dissemination of the other parts – the ‘second’ (edited by S. P. Brock in 1995) and ‘third’ (of which an edition by S. Chialà is forthcoming) – was limited to the Syro-Arabic Christian communities. Considering this impact, one cannot but regret that until recently there were almost no detailed studies of Isaac's heritage. Two notable exceptions are W. Thomson's – unfortunately, scarcely known and somewhat outdated – unpublished thesis ‘Isaac of Nineveh: a study in Syrian mysticism’ (Harvard 1924), and Chialà's Dall'ascesi eremitica alla misericordia infinita: ricerche su Isacco di Ninive e la sua fortuna (Florence 2002) which provided a full introduction to Isaac's theology and literary heritage as well as the posterior influence of his corpus. In this respect Hagman's monograph is very welcome, for it offers a thorough treatment of Isaac's ascetic system.

Isaac was born in the region of Beth Qaṭraye, somewhere on the western coast of the Persian Gulf, and lived as a solitary in the mountainous region of Khuzistan in south-eastern Iran. His floruit is usually placed in the second half of the seventh century. But his remoteness from a modern reader is not only in space and time, but also – and that is what makes him a ‘dark’ and difficult author – in terms of a cultural, religious and existential heterogeneity which is foreign to a reader who comes from the modern situation of the decline of ascetic values. This is a main premise that determines Hagman's approach and objectives. Apart from being a cogent historical investigation of Isaac's ascetic doctrine, another achievement of Hagman's research is that it is a timely attempt to present and interpret this doctrine purporting to disclose a quasi-invariable and universal situation that stipulates a presence of asceticism as a condition sine qua non for a Christian.

The first chapter presents an overview of modern scholarly discussion of asceticism in order to demonstrate how asceticism is approached from various directions (with special attention to the works of the North American ‘asceticism group’ and of R. Valantasis) and thereby to set a framework for the ensuing treatment of Isaac's ascetic doctrine.

Chapter ii gives a clear and concise introduction to Isaac's life and his place in the East Syriac ecclesiastical tradition. The doctrines of its main theological authorities (Theodore of Mopsuestia, Evagrius Ponticus and others) provide a background against which Isaac's thought is studied in the following chapters, in which the author always tries to trace the origin of a particular notion of Isaac. This chapter also includes a very helpful sketch of Isaac's theology (Hagman notes its individualistic character) which helps the reader to follow the author's thorough investigation of Isaac's ascetic ideas.

Chapter iii aims to analyse the role of the body in asceticism. Taking as a point of departure modern philosophical and anthropological discussions regarding the body, the author explores Isaac's ambivalent attitude towards it. Thus, while he regards the body (and man in general) as having a positive character (especially, in worship) indispensable for spiritual development, it is the very same body (Hagman argues that body in Isaac serves as a multivalent, symbol) that is considered as a location of forces that impede spiritual progress.

Chapter iv deals with the polysemantic concept of the ‘world’ for Isaac and reveals its different ‘symbolic’ meanings, all of which centre around a negative understanding of the world (a synonym for ‘society’) as a place that ‘exploits the passions in humans’ (p. 110).

Chapter v studies the different meanings of ‘fear’ and comes to the conclusion that, for Isaac, ‘overcoming fear is truly salvation, because it releases the individual from the grips of sin inherent in this world’ (p. 124).

Chapter vi is devoted to the consideration of common monastic ascetic practices (solitariness, fasting, vigils and prayer) while aiming to demonstrate the ‘symbolic’ meaning that can be observed in their communicative function: to convey to society the ascetic's world-view.

Chapters vii and viii demonstrate how Isaac's treatment of ecstasy, spiritual knowledge and humility contribute to a fuller comprehension of the main purpose of asceticism, viz. ‘to become like God’ (p. 195), and explore Isaac's perception of the future world. The most significant insight of the author here is an accent on communicative features of eschatology, purporting to convey the radical difference of the world to come.

Chapter ix serves as a general conclusion to the study and sets to the fore the key notions (‘world’, ‘body’, ascetic practice) in the ‘grammar of Isaac's asceticism’ in their multivalent usage. A proper understanding of this grammar enables us to reconstruct Isaac's model of an ascetic life: the ascetic is situated between two worlds, and attempts by way of a total modification of personality to communicate to the present world a radically different world-view, that of the world to come. In this respect, according to Hagman, an ascetic functions in the same way as an icon.

The book concludes with a useful survey of studies on Isaac and his corpus, followed by a bibliography (though a more complete bibliography can be now found in G. Kessel and K. Pinggéra, A bibliography of Syriac ascetic and mystical literature, Leuven 2011), and indices of subjects and names.

There are some infelicities, like an unclear system of abbreviations. It is only by way of a personal deduction that one can figure out that the abbreviation ‘DS’, which appears quite often in the footnotes refers to the unpublished section of the ‘second’ part available in P. Bettiolo's Italian translation (Isacco di Ninive: discorsi spirituali, Magnano 1990). There are also mistakes in the transcription of Syriac words, and in quotations in Syriac.

Despite its slight imperfections, however, this coherent study will undoubtedly prove to be an important contribution not only to the field of Eastern Christian studies, but also to more general and interdisciplinary theological discussions.