This companion to Gardner's Chemical Synonyms and Trade Names offers a major expansion of the information provided for individual chemical compounds. It contains 4,174 chemical entries and information on their structures, molecular formulas, and chemical names, and provides synonyms for each chemical, as well as other identifiers, trade names, and trivial names, in English and other languages. It gives information on chemical properties of the compounds, known uses, and biological data. The reference also lists manufacturing and supply companies. Material is indexed by chemical name and synonym, CAS Registry number, and EINECS number. Milne is retired from the National Institutes of Health.