This book is a collection of state-of-the-art research works in the field of materials science. Specifically, the works deal with issues related to the welding, joining and coating of metallic materials. These methods are known as main processes in the field of metallurgy, and are usually applied in order to solve complex problems of joining metals or the fabrication of metallic surfaces with required properties and performance. The focus of this book is on metals such as aluminum, magnesium, titanium, various types of steel, intermetallics and shape memory alloys. These scientific works address microstructural evaluation, as well as the performance of the produced joints and coatings. Scientists from all over the globe have presented novel advances and possible solutions for metallic materials joints and coatings for applications in the automotive, aerospace, chemical and medical industries, among others.