About 90 per cent of the 10,000 known species of the Crustacea Decapoda live in oceans and adjacent coastal and estuarine regions, and most of them pass through a complex life history comprising a benthic (juvenile-adult) and a planktonic (larval) phase. The larvae show a wide array of adaptations to the pelagic environment, including modifications in their functional morphology, anatomy, the molting cycle, nutrition, growth, chemical composition, metabolism, energy partitioning, ecology and behaviour.;All these traits are reviewed in this volume, attempting to promote an integrated, multidisciplinary view of the biology of larval Decapoda and other crustacean taxa. Emphasis is placed on the lesser-known anatomical, bioenergetic and ecophysiological aspects of larval life, as morphology has already been extensively documented. Changes in biological parameters (for example, rates of feeding, growth, metabolism) are shown in successive developmental stages, within individual stages, and as responses to environmental factors. Particular attention is paid to interrelationships between intrinsic phenomena (molting cycle, organogenesis, growth) and the overlaying effects of extrinsic factors (for example, food, temperature, salinity, pollution). Concluding from the available data, major bias and gaps in present knowledge of larval biology are identified and discussed as to their potential significance in future research.