This book was written for the honour and increased reputation of Wibert, monk of Christ Church Priory, Canterbury, sometime subprior? 1140–53, prior 1153–67. He had been appointed prior by Archbishop Theobald, after three unsuitable predecessors. His obit records his gift of vestments and treasures for the church and the provision of a giant bell for the campanile. He had restored to the priory a wood on the manor of Chartham, and a rent which was to be spent in the refectory, for the poor and for almsgiving at a festival. He had built a water-system to bring water to the priory and convey it through the precinct. He left money for the cappa (cope) that he had intended to make, here extended to capella (chapel). Apart from this possibility, there is no mention of buildings, but naturally it might be supposed that Wibert built those necessary for the water-system. In addition there are the two drawings in the Eadwine Psalter (Trinity College, Cambridge, ms R.17.1), which Professor Willis understood as explanations of Wibert's water-system, though the large drawing is a depiction of the priory within the city wall with its buildings through which the water-pipes are threaded. Willis (1868) dated it to 1165. Fergusson's study depends partly on the evidence of the drawing, but he understands it not as a plan of the water-system, but as ‘a view of Christ Church as an idealized Civitas Dei [City of God]’ like Jerusalem seen as ‘a metaphorical heavenly city’, and dates it to 1158. He supposes that, apart from Lanfranc's dormitory, almost the whole precinct was built or rebuilt by Wibert: from the nature of his architecture the man is revealed as a `figure of unusual intelligence and ambition whose wide ranging interests ran in tandem with his control of resources’. Since the late 1970s a great deal of effort has been expended in the precincts, especially in relation to archaeology and building surveys which have provided further evidence in addition to Willis's survey. Much further investigation in archaeology, inspection of standing buildings and documentary study will be required to evaluate Fergusson's suggestions. An example of such study is to be found in appendix C, a note by Professor Christopher Wilson on ‘Mystery marble’ or the origins of what has been called ‘onyx marble’, used for polished shafts in Wibert's architecture, stone now revealed as ‘calc-sinter’ a limestone deposit from a former Roman aqueduct in the Eifel hills. Stuart Harrison also has a share in the book, with excellent photographs, computer models and many comparisons with Yorkshire monastic sites.