This volume has been authored by internationally reputed experts from Japan and Europe and reflects the state of the art in the field of pediatric surgery. The first section on constipation and incontinence shows the fast pace of research in Japan on the subject. In particular, pathophysiological studies have led to improved diagnostic techniques and the clinical application of anorectal manometry. The second section discusses a topic that has long been of great interest: motility disturbances of the gut. New insights from improved diagnostic methods, pathophysiology and histology have induced new therapeutic trials and a better understanding of diseases such as Hirschsprung's disease and neuronal intestinal dysplasia. Despite the many recent improvements, much clinical and experimental work remains to be done to resolve these problems.