This book provides selected contributions of the 4th International Conference on Advanced Joining Processes, held in Coimbra, Portugal, on October 16–17, 2025.   Researchers from over 25 countries presented their innovations in this field. In order to disseminate the work presented at the conference, 13 papers were selected for this volume.The focus of this volume is on the most recent research topics concerning joining by plastic deformation, adhesive bonding, welding, and additive manufacturing. The book is a state-of-the-art of advanced methods of joining and also serves as a reference volume for researchers and graduate students working with advanced joining processes.