Welding refers to the science and practice of joining metals and thermoplastics by using fusion and related techniques like soldering and brazing. The most common methods associated with this area are gas metal arc welding, shielded metal arc welding, electroslag welding, gas tungsten arc welding, etc. The aim of this text is to give students a deep insight about the various methods and technologies used in this field. Most of the topics introduced in it cover new techniques and applications of welding. Different approaches, evaluations and methodologies on the subject have been included in it. The textbook will serve as a valuable source of reference for those interested in this field.