The monograph has been written keeping in mind the researchers and practicing technologists designing and working with 18 % Ni maraging steels. These steels have been the subject of several publications over the years and the focus of the book has been to review and document the progress made over the last three decades with reference to their metallurgy, production and application. Analysis and prevention of failures encountered in critical production processes – melting, hot working and heat treatment – forms an important part of the book. The monograph also addresses fusion welding of maraging steels, the dominating method of joining these steels. Environment-induced degradation is a major issue when it comes to working with maraging steels and the book dwells on this aspect. Successful attempts have been made by the author and his coworkers to optimize melting, hot working, heat treatment and welding procedures to realize the best combination of strength and fracture toughness in both base metal and weld joints. If this book inspires further research and development on this group of steels and increased exploitation of their potential, the purpose can be said to be achieved.