There is a tendency, in these days of steadily increasing enthusiasm for excavation, to overlook the very considerable body of Greek and Roman literature extant which deals with the geography and history of the British Isles during the Roman occupation (43–410 A.D.) Few people have studied all the evidence; few history books pause to discuss the authorities for such familiar stories as those of Caratacus and Boudicca, or even to spell their names correctly. The reason is that many of these documents have never been edited in England, and no attempt has been made to collect them in handy form, and discuss the date, purpose, and value of each. The purpose of this article is to review the most important authors and estimate briefly the value of the contribution of each. There are no fewer than 49 writers in Greek and 79 in Latin who make direct mention of the British Isles; and though it is true that many of these do little more than mention them, or repeat the statements of previous authorities, we are still left with a number of independent sources of information.