More than 100 years after Karl Josef Bayer invented the Bayer Process for the production of aluminum oxide, new uses are still being found for this material. in advanced ceramics, separations and catalysts, the manufacture of integrated circuits as well as in composite systems. This revised edition of Alcoa Laboratories Technical Paper No. 19 includes discussions of how our understanding of the structure and properties of aluminum oxides has progressed since the original was published in 1972. The first Technical Paper on this subject was published in 1953 by Dr. Allen S. Russell.