Description:The growing field of conservation biology has placed a new value on cataloging the Earth's living creatures, even as many of them face extinction. In the first systematic revision of the Chrysidid wasp family since 1889, the authors present a worldwide overview of this colorful group. Some 3,000 valid species have been named and are arranged in 84 genera and four sub-families. This comprehensive treatment presents a reclassification of the generic and higher taxa. It also includes a summary of previously published information, indicated problems in need of further study, and detailed synonomic species lists for each genus. Discussions for each tribe and sub-family include ancestral characteristics, phylogenetically important characters and a corresponding cladogram, keys to genera, and relationships among taxa.