Bartlett modestly claims that while his book has a ‘fairly grandiose’ title, it does not aim at ‘comprehensiveness but, I hope, at illuminating examples and general considerations’. In the first of four chapters, on ‘The boundaries of the supernatural’, he demonstrates a growing sense from the twelfth century onwards of a dualism of nature, which follows a pattern of causes implanted by God in creation, and of things beyond nature, the causes of which are reserved to God alone. He then tackles the problem of where the boundaries lay between the two, how they were sought and whether they shifted in a direction that resulted in a contraction of the sphere of what became commonly called the supernatural, particularly following the arrival in the twelfth and thirteenth centuries of growing numbers of translations of books by Aristotle devoted to natural philosophy and science. But some natural forces were occult such as those which resulted in marvellous happenings and ‘the miracles of demons which are performed by magic arts’ (Aquinas). The miracles worked by God and the saints were not of this kind. But there too difficulties arose because no one wanted a God who was unnatural. Chapter ii takes us into physics: the material universe seen as a machine, as moving spheres and as elements in motion. But how should eclipses be explained? By the physical regularities of orbiting spheres or by the activities of magicians and monsters or as signs of something else? Chapter iii brings the world's inhabitants before us, not just angels and demons, humans and animals, but swarms of women who fly by night, creatures with dog heads on human bodies, and other exotic people living beyond the known world. Chapter iv, on Roger Bacon, begins with an amusing account, so familiar in our time too, of his grumbling about the inadequacy of the teaching of mathematics, science and foreign languages, especially Arabic. Bartlett writes that his examples have been selected ‘in a cavalier fashion from many centuries’ (p. 111), but in truth his chapters are full of pertinent and fascinating material, strikingly illustrated with photographs, and richly providing a sustained, broad view of key, mysterious outlooks and images that developed and declined over long periods. This is a fertile book that could be written again with other sets of examples that would further illustrate debates over boundaries. Plato and Platonism are but briefly mentioned but Plato's Timaeus was fundamental for cosmology in the twelfth century and, arguably, the nominalists of the fourteenth century were soon to reshape scientific thought far more than did the apocalyptic and realist friar Roger Bacon.

Other sets of examples (not excluding Platonism) are plentifully provided in a remarkably learned and original book by C. S. Watkins on History and the supernatural in medieval England. Many, if not most, readers of medieval English historical writings skip over their tales of strange ‘supernatural’ events that seem digressive and far-fetched, tales, for example, about fairies, green children, spells, portents, visions and prophecies. Not Watkins, however, who sees these ‘curious exotica’ as means by which the historians themselves tried to make sense of their world and also as means by which we can make sense of theirs. The book deserves a subtitle since the historians studied here – Orderic Vitalis, William of Malmesbury, William of Newburgh, Richard of Devizes and others – and the religious and magical beliefs and practices that they relate, lived and wrote between c. 1050 and c. 1215 and largely in the Anglo-Norman realm. But the lack of a subtitle serves to draw attention to the importance of the effort which Watkins puts into understanding the singularity of the religious cultures in this period when set against the longer history of religious and folkloric beliefs and practices in medieval England. Watkins acknowledges that religion in the century or so after the Conquest period was largely consensual but he also shows how very diverse it was too. He distrusts arguments for the survival into the Anglo-Norman world of the vague remains of earlier pagan beliefs and practices which, he argues, had become disarticulated from the beliefs which had produced them, and now carried different meanings: the continuities are illusory and, tellingly, were not identified as pagan vestiges. Watkins also holds that the obligations placed upon believers before, say, the Fourth Lateran Council in 1215 lacked the clarity and the universality that they later came to possess. Manuals of confession and collections of exempla written c. 1200 provide evidence which seems to Watkins to be coloured by normative conventions and by a deep literary indebtedness to older works, whereas the writers of narrative works in the twelfth century were often more free to express and accept what would later seem to be confusion. Watkins sheds a ‘two cultures’ approach. The antitheses familiar to historians of medieval religion – elite/popular, clerical/lay, learned/unlearned – give way to loose synthesis. The focus here is on communities in which unofficial and official beliefs and practices (many apotropaic – a much-used adjective) were found together and, crucially, shared by parish priests and even archdeacons, and by writers of histories for they too were drawn from, and lived in, worldly communities whose local, place-bound outlooks, experiences of the mysterious, and folkloric practices were and remained theirs too, being accommodated in compromises with the formal teachings and rituals of the Church. Watkins's fine achievement is to bring to life the many shifts in understanding of what should be made of wonder stories which could not be altogether written off yet appeared ambiguous when related to reliable testimony and rational thought. The ‘supernatural’ before the thirteenth century was richly anomalous.