He was a German physical chemist and metallurgist who was the first to make chemical metallurgy an exact science. He focused on the wide-ranging field, such as oxidation rate theory, catalysis, corrosion, batteries, fuel cells, and crystal defects. He wrote the paper with Walter Schottky that helped in bringing order to the field of defect structures in solid-state materials. Wagner was also known as “the father of Solid-state Chemistry” and also remembered as one of the greatest in physical chemistry.