The focus of this article is how the practice of metallurgical techniques was brought together with science in the 17th through 19th century. Initially, the fact that empirical development of metallurgy was far beyond theoretical understanding meant that the great advances in physics and chemistry of the 17th century had little impact on metallurgical industries. This situation changed by the beginning of the 19th century, by which time the presence of carbon had been recognized as the characteristic that changed iron into steel. At the same time, mechanical engineers began to make contributions to metallurgy through discovery of the microcrystalline structure of steel, and the mathematical theory of elasticity led to a quantitative approach to testing of mechanical properties of steel. Diverse alloys began to be produced by the end of the 19th century. Structural components and automobiles provided incentives for some of these developments. The history of the introduction of useful aluminum during the 19th century is more closely tied to scientific developments. The article closes by noting that many metallurgical advances came about through accidental discoveries by artists or other practical, non-scientific metallurgists.