The new edition of the third volume of our manual, whose first edition sold out in a relatively short time, has experienced an unintended delay due to some adverse circumstances, including the prolonged illness of one of the authors. Mr. Baurat Dipl.-Ing. R. H. Anchen has retired from our team due to his advanced age. He has been succeeded by Dr.-Ing. J. Ruge, the head of the Welding Technology Training and Testing Institute in Munich, who will be responsible for the main sections. The further development of welding technology necessitated a complete revision. The content has been expanded to include sections on calculating and designing spot weld connections, as well as welding in vehicle, bridge, and shipbuilding. A new section on the fundamentals of lightweight construction has also been added. All sections have been critically reviewed in light of the guidelines and standards developed in the meantime, and new examples have been included. Tabular and graphical representations are intended to facilitate the calculation of welded structural elements. The purpose of this book is to introduce young engineers and designers who are still unfamiliar with welding construction to the calculation and design of welded structures, paving the way for a technically sound understanding of welding. Basic knowledge of welding and familiarity with the operation of welding processes are assumed. The section "Calculation of Welded Structures" contains the fundamental concepts of static and dynamic loading, which are essential for assessing the strength behavior of materials and for the calculation of welded structural elements.