Straightforward considerations first: there are several collections of excerpts from sources, providing historical introductions as well as translations. They make a good first port of call for students, or for teachers who are themselves non-specialists but are thinking of offering a class or two on Byzantium. The earlier period, roughly corresponding to our Part I, is well served by sourcebooks. Michael Maas covers most aspects of life in the Byzantine sphere from the era of Constantine the Great’s conversion until the Arab invasions of the seventh century, general remarks being interwoven with extracts from relevant texts.1 Maas gives details of websites dedicated to more specialised source-guides and collections of texts. A wide-ranging assortment of texts bearing on religion, whether Christian or non-Christian, is provided by Douglas Lee with substantive introductory paragraphs,2 and collections of texts relating to doctrine and the disputes and councils arising therefrom are available.3 The empire’s eastern frontier is the subject of a very full narrative sourcebook.4 The middle and later Byzantine periods – effectively our Parts II and III – are covered in their entirety by very few sourcebooks. The contrasting civilisations of Byzantium and Islam are presented by Charles Brand, while Deno Geanakoplos supplies a broad overview of the Byzantine world from Eusebius’ time until the Italian Renaissance.5 Sourcebooks focusing on particular themes are more plentiful, for example the well-chosen collections of saints’ lives in Byzantine defenders of images, and in Holy women of Byzantium.6 The former is devoted to the iconoclast controversy, for which other translations and authoritative guidebooks exist.7 Fields in which the Byzantines had close dealings with other peoples have generated sourcecollections, for example, on medieval trade,8 the Christianisation of the Slavs,9 the world of Islam,10 the Normans or crusading.11 These can be illuminating, even while offering different perspectives, often hostile towards the Byzantines. The loss of so many written source-materials from Byzantium is one reason why we depend heavily on outsiders for knowledge of, for example, the layout of Constantinople itself, fortunately a subject of keen interest to pious Rus travellers.12 But there is something about Byzantium, whether as political structure or cultural atmosphere, that resists categorisation or orderly review in the manner of, say, imperial Rome. And now both sourcebooks and general guides to sources in translation have rivals on the internet. A reliable general guide to printed translations was provided by Emily Hanawalt,13 but future guides and source-collections will probably appear mainly in cyberspace.Online guides offer accessibility together with high-quality scholarship, as witness the collections of Paul Halsall and Paul Stephenson.14 An authoritative online survey of translations of saints’ Lives in print is also provided by a bastion of Byzantine studies in the Anglophone world, theDumbartonOaks Research Center inWashington, DC.15 Internet guides are open to constant updating, an asset that may have its disadvantages. But they are well suited to Byzantium, in their ability to bring together sources and resources widely scattered across disciplines and geographical space, ready for use by newcomers or by long-time scholars. And, as a medium, the internet offers direct and flexible access to important source-materials, since the visual arts and archaeological data can be presented in various degrees of detail, in high definition but at minimal cost.