Should the practice of religion impinge upon the public sphere, or is it a private and individual matter? From its beginnings in the 1380s, the Low Country religious grouping known as the Devotio Moderna developed a way of life which was both determinedly communal, in the mould of the first Apostles, and wedded to the pursuit of ‘interiority’.

John van Engen, Professor of History at Notre Dame University, justifies his translation of Devotio Moderna as ‘Modern-Day Devout’ on the grounds that his subjects' lives were neither constrained by past norms nor yet prefiguring a Reformed future. For them, ‘modern’ meant that their spirituality and the lifestyle it prompted were rooted firmly in their immediate context. Like the mendicants, with whom they were to develop a complex relationship, the Devout flourished in urban environments. Manual work not only held spiritual significance but offered a degree of economic independence necessary for a life in the world but not of it; they built their own houses (including the women), worked as bookbinders, copyists and textile workers, and ran a series of hostels and schools for boys, including the young Erasmus.

It was books which bridged the gap between the Devout's private and public identity. The Word of God was central to Devout ‘self-making’, and writing became the public expression of their interiority, as they set down on paper their self-exploration. Though they were a long way from the mindset of the Reformation, the Devout none the less stood for some of the values that were to become so bitterly disputed, not least access to vernacular Scriptures and discussion of the Word (though they cleverly rebutted accusations of illicit lay preaching and teaching), an alternative approach to confession and spiritual guidance.

The history of any spiritual movement is rooted in its distinctive interpretation of the interplay between personal religious response and the extent to which that response is nurtured, or otherwise, by existing structures or institutions. Van Engen sets the Devout's long struggle for recognition from both ecclesiastical and civic authorities in its historical and theological context; notably the fear of heresy which hung over so many new religious movements, particularly those that attracted women (the word ‘beguine’ was often used disparagingly of the Devout) and the Franciscan disputes about the doctrine of the poverty of Christ which overshadowed the Devout's commitment to communal property. The ongoing question of authority and obedience in a voluntary community without vows is examined against the backdrop of a Church undergoing its own prolonged crisis of authority following the papal schism of 1378.

The Devout's deliberate choice not to take vows or become an order placed them in an uneasily liminal space between public and private, religious and lay. The title ‘Sisters and Brothers of the Common Life’ expresses more accurately than ‘Modern-day Devout’ their intense focus on communality of purpose as well as property, but the titles ‘brother’ and ‘sister’ were themselves problematic. The right of lay people to live together without vows was questioned, as was their commitment to chastity and virginity. While they did not wear a formal habit, their deliberately poor dress was a statement of otherness. Van Engen repeatedly emphasises this cultivation of difference, a conscious oddness in manner and appearance matching their own sense of having been irrevocably set apart by a conversion experience.

Devout women's houses have not bequeathed historians such a wealth of documentation as the men's, but among those accounts we do have are some energetically written sisters' Lives which read much more personally than the stylised vitae of medieval women saints. The Devout placed great emphasis on consensus and mutual responsibility within the life of each house, and the sisters describe with touching realism the difficulties of the common life, made more acute by their ambiguous status. Van Engen tracks the Devout as they deal with these discomforts by following to some extent the trajectory familiar to all religious movements, from inspiration through experiment to institution. Growth in numbers and the practicalities of daily living inevitably demanded a degree of structure. The way in which the Devout live out their desire to imitate the first Christians, even as pragmatism reshapes their intentions, inescapably suggests parallels with the early Franciscans, and indeed some later chose to become tertiaries for the sake of a greater degree of ecclesial protection. Others became Augustinian canons, Cistercians or Carthusians, or adopted voluntary enclosure, easing the tension inherent in trying to live a life often viewed with equal suspicion by mendicants, parish clergy and townspeople. Still others fought energetically to justify that life in legal and theological apologia, and to maintain it through periods of exile.

As he recounts the history of the Devout, Van Engen's style is for the most part engagingly readable, though it occasionally lapses into an informal tone which grates somewhat in an academic text.This solidly researched study also deserved a more attentive editor: the book is littered with minor misprints and spelling errors, from the irritating (principle/principal) to the unintentionally amusing (‘the parable of the sewer’). Nor is the internal structure always helpful; by the time we reach an expanded discussion of the Devout's theological rationale in chapter 7, many of the concepts raised have already been touched upon.

The promised exploration of the Devout's ‘self-making’ is never quite delivered. In the sharing of their private rapiaria (a cross between a scrapbook, a commonplace book and a journal) the very interiority that they sought became a community pursuit and resource, rather than a purely individual exercise; this process is most famously and lastingly exemplified by Thomas of Kempen's Imitatio Christi. Relating the Devout's pursuit of interiority to an examination of what exactly it was that they were seeking to imitate could have resulted in a deeper exploration into the concept of self and identity in the fifteenth century than Sisters and brothers of the common life ultimately manages to achieve.