The Japanese beetle, Popillia japonica Newman, an introduced scarab, has become the most widespread and destructive insect pest of turf, landscapes, and nursery crops in the eastern United States. It also damages many fruit, garden, and field crops. This review emphasizes recent research on the beetle's biology and management. Adults feed on leaves, flowers, or fruits of more than 300 plant species. Adaptations mediating their host finding, dietary range, mating, and oviposition are discussed. We also address abiotic and biotic factors affecting population dynamics of the root-feeding larvae. Japanese beetle grubs are widely controlled with preventive soil insecticides, but options for remedial control of adults and larvae presently are limited. Advances in understanding host plant resistance, entomopathogens, and other biorational approaches may provide more options for integrated management. Despite ongoing regulatory efforts, the Japanese beetle remains a threat as an invasive species.