The last fifteen years have witnessed the extraordinary evolution of basic and clinical research in the field of lysoso-mal storage diseases (LSDs), transforming many of them from dire, untreatable progressive diseases to conditions that allow for possible cure or mitigation. In addition to the presently employed techniques of haematopoietic stem cell transplantation and enzyme replacement for a number of lysoso-mal storage diseases, other therapeutic approaches are being developed that are based on different principles. The awareness that the efficacy of treatment is greater if adminis-tered at the first signs of disease or, even better, during the pre-symptomatic phase underscores the urgency of early clinical diagnosis. Efforts are being made to improve the clinical acumen of paediatricians, paediatric surgeons and neurologists, rheumatologists, orthopaedists, and other professionals who come into early contact with children with LSDs. The possibility of including some of these disorders in routine neonatal screening is also a matter of discussion. This volume provides an updated overview of epidemiologic, biochemical, genetic, pathogenetic, and clinical aspects of these disorders and outlines the various treatment options currently available for the LSDs. The need for patients with rare diseases like LSDs to be followed-up in a specialised centre is emphasised in view of the many kinds of multidisciplinary treatment that are needed to improve the quality of life and survival of these children.