About 95 per cent of all known animal species are invertebrates. A knowledge of their sexual, reproductive, and developmental biology is essential for the effective management of species that are economically useful to man or are harmful to him, his crops, and livestock. This treatise is the first to cover all aspects of reproduction and development of the entire spectrum of invertebrates terrestrial, marine, freshwater, brackish-water, free-living, and parasitic. The chapters, by leading world experts in their fields, are up-to-date and informative, and suggest a number of problems for future research.