The book comprises three parts. Part 1 gives a historical description of the development of ironworking techniques since the earliest times. Part 2 is the core of the book and deals with the metallurgical basis of microstructures, with four main themes: phase diagrams, solidification processes, diffusion, and solid state phase transformations. Part 3 begins by an introduction to steel design principles. It then goes on to consider the different categories of steels, placing emphasis on their specific microstructural features. Finally, a comprehensive reference list includes several hundred pertinent articles and books. The book is the work of a single author, thus ensuring uniformity and concision. It is intended for scientists, metallurgical engineers and senior technicians in research and development laboratories, design offices and quality departments, as well as for teachers and students in universities, technical colleges and other higher education establishments.