Nanotechnology -- the manipulation of matter on a near-atomic scale to produce new materials and devices -- has the ability to transform many industries, from medicine to manufacturing, and the products they produce. Nanomaterials may present new challenges to understanding, predicting, and managing potential health risks to workers. Many knowledge gaps still remain on how to work safely with all of these materials. Through strategic planning, research, partnering with stakeholders, and making information widely available, the National Institute for Occupational Safety and Health (NIOSH) is working to continue to provide national and world leadership in providing solutions that will prevent work-related illness and injury. NIOSH hopes to raise awareness of the occupational safety and health practices that should be followed during the synthesis, characterisation, and experimentation with engineered nanomaterials in a laboratory setting. This book contains recommendations on engineering controls and safe practices for handling engineered nanomaterials in laboratories and some pilot scale operations. The book was designed to be used in tandem with well-established practices and the laboratory's chemical hygiene plan. As our knowledge of nanotechnology increases, so too will our efforts to provide additional guidance materials for working safely with engineered nanomaterials.