Patients affected with a hernia continue to represent a significant clinical population. Resulting from varied causes and associated with an array of pathophysiologies, a hernia can pose marked diagnostic and treatment challenges for the clinician. Sometimes sub-clinical and sometimes life-threatening, a hernia may require little or substantial medical intervention. This book consists of sixteen chapters by noted clinicians and scientists. Many chapters include background pathogenesis, typical symptoms experienced by patients, diagnostic measures, and therapeutic approaches. Current information is summarised and interpretations offered where appropriate. Basic pathogenic mechanisms and pathophysiology are considered in chapters such as those on the inheritance of a groin hernia (Burcharth and Rosenberg), and on alterations in arterial blood gases both before and after surgery (Tsounaki). These chapters make evident both the progress made in understanding the processes underlying hernias and related diseases, as well as the incomplete understanding we have with respect to such processes. Descriptions of clinical presentations, diagnostic approaches, and medical and surgical management are provided for several types of hernias, including inguinal, diaphragmatic, incisional, and Richter's. The utility of new methods for correction, such as laparoscopy and components separation, is described in the chapters by Maxwell and Baird, Marescaux et al, Mazzochi et al, and Sabino et al. These chapters reflect the technological improvements that have been brought to the successful treatment of hernias. It is likely that, with time, further definitions and refinements will additionally advance the understanding and approaches to hernias. The goal of this book is to summarise our understanding of basic concepts of hernia, at present, as a reference for scientists and clinicians.