Over the last two decades, there have been major advances in imaging, endoscopy, and laparoscopy in the field of gastrointestinal (GI) surgery. GI surgery is the newest sub-specialty branch of general surgery, where enhanced expertise and high-volume centres have made a difference to the outcomes of complex operations. Surgeons can now perform difficult procedures with low morbidity and mortality rates, and greatly improved overall results. This volume provides detailed and up-to-date information on diseases of the mesentery, omentum, peritoneum, and retroperitoneum as well as abdominal trauma. As an area of surgery that may often be neglected in traditional teaching, with limited resources to aid clinical decision making, diseases and trauma in this area can lead to situations where even the most experienced surgeon may feel challenged. Managing patients with these diseases successfully warrants a comprehensive knowledge of their anatomy and physiology as well as the pathology involved. The book provides comprehensive coverage of the different conditions and traumas, and includes a final chapter covering abdominal surgery during the COVID-19 pandemic. Written and edited by international experts in the field, this book will be a valuable resource for abdominal, peritoneum and retroperitoneum surgeons and trainees, general surgeons, researchers, and medical students.