The book emerges as the product, not merely of the named writers and editors, but of a community of scholars whose assistance most of the authors acknowledge. The reader's effort in comprehending such detailed scholarship will be fully rewarded by the knowledge gained. In this twenty-first century of wars, droughts, terrorism, bushfires, and epidemics, the barbarians may be gathering, but for as long as learned books such as this continue to be published, we can trust in the drawbridge staying safely raised.