Richard J. Lewis, Sr., is a chemist with extensive experience in air and industrial pollution measurement, industrial hygiene research, and toxicological and chemical information systems. Formerly manager of information systems for the National Institute for Occupational Health and Safety, Lewis is the author or coauthor of a number of widely used references, including Sax's Dangerous Properties of Industrial Materials, Rapid Guide to Hazardous Chemicals in the Workplace, Reproductively Active Chemicals, and Hawley's Condensed Chemical Dictionary, all published by Wiley.