This book focuses on the toxicity of engineered nanomaterials (ENMs) and their underlying physicochemical, cellular, physiological, and molecular mechanisms. Further, it covers ENMs' translocation and their targeted organ toxicology, and discusses chemical and pharmacological strategies used to combat nanotoxicity. Engineered nanomaterials (ENMs) are defined as materials with one or more dimensions of less than 100 nm, and have shown considerable promise in several areas of development. At the same time, the potential toxicity of ENMs for human health and environmental organisms is increasingly attracting attention. In addition to the typical properties of model animals, Caenorhabditis elegans is extremely sensitive to environmental toxicants, which makes it the ideal in vivo assay system for toxicological studies. C. elegans has been widely used in toxicity assessment and toxicological studies of environmental toxicants and stresses. This book provides a comprehensive summary of nanotoxicology research on C. elegans.