Covers about 240 British species in the microlepidoptera families Yponomeutidae, Epermeniidae, Schreckensteiniidae, Coelophoridae and Elachistidae. It is illustrated with colour plates of adults, with illustrations of selected larval cases. Distribution maps are provided for all species on a vice-county basis. Also included is a special introductory chapter by David Agassiz on established migrant and adventive Lepidoptera in the British Isles.