Elachistine moths are the World's most species-rich group of Lepidoptera that specialise on monocotyledon plants, especially grasses and sedges. This volume is the first reference to describe the so-far unknown diversity of these leaf-mining moths in Australia. It provides a new generic classification for the group on a worldwide basis, and describes in detail the genera and species that occur in Australia. Keys to genera and species, as well as generic, subgeneric and species group descriptions are given, richly supplied with illustrations of larvae, pupae and adult moths. In addition, the external appearance and the male and female genitalia of all species are described. The volume contains redescriptions of all 11 previously named valid species, and descriptions of no less than 137 species new to science, of which 128 are formally named, increasing the known species richness of Australian Elachistinae by more than an order of magnitude. The diverse Australian Elachisine fauna is nearly entirely endemic, and concentrates on the more humid coastal and montane regions. Given the wealth of biological information, the book provides a basis for conservation consideration of Elachistinae, many of which are dependent on diminishing fragments of suitable habitat.