This article reviews the present state of insects, describing their taxonomic position, cost, and value as well as the threats to their well-being. Insects are an important source of both ecosystem services and ecosystem disservices. Recent studies have indicated a worrying decline in insect species, especially in flying insects in the northern temperate region, and this has spawned much media attention. Some decline has occurred, it is clear, due to agricultural intensification, urbanization, overuse of pesticides, and global climate change. A decline would seriously affect the ecosystem services that insects provide. However, there is too little data to warrant the belief that all insects are declining everywhere. There is a pressing need for more basic research on insect diversity in the context of a changing world.