Book excerpt: There are certain key alloys, stainless steels, nickel alloys, and low alloy steels that are of paramount importance to the power generation, petrochemical, and oil and gas industries. Addressing the significance of such alloys and their role in these fundamental industries, The Alloy Tree includes the following key features: * a short introduction and a master flow diagram that shows the interrelationship between the main alloy groups * a detailed exploration of how stainless steels, nickel alloys, and some low alloy steels have evolved from plain carbon steel * an explanation in each chapter of the background, development, key properties, and applications of the alloy type covered.