The book lists 1329 compounds of which 322 were reported to cause malignant tumors in animals and 35 others to induce only benign ones. The work lists only single compounds. Such complex mixtures as tars, irradiated sterols and articles of diet are not included. Mixtures of two or more compounds given simultaneously are generally excluded. Since the mass of short term pharmacological observations in the literature are not informative as regards tumor-producing potency, only compounds on which observations have been made for at least one month after the first administration have been included. The applications of chemical compounds to all vertebrates excepting fish have been considered. The action of carcinogens on fish, flowering plants, yeasts, bacteria, tissue cultures, isolated tissues, and the like has not been covered. Names have been altered to conform to the Chemical Abstracts system. In addition, trade names and alternate chemical names have been placed in the index of compounds to help in locating certain compounds.