"Preface The Earth surface is changing in an exponential way. These days our technological society and its demographical growth are impacting all natural resources with higher intensity than during the entire history of mankind. As a result of a plethora of perturbations (erosion, contamination, salinization, acidifi cation, urban and industrial sealing, etc.) biosphere and the surface of the geosphere are being degraded or removed. Soil resources are vital to ensure the production of food to meet the world's increasing population as well as the support of life on the planet. However the pedosphere is subject to many risks and only in the last years has society begun to recognize that it must be preserved as part of our biological, geological and cultural heritage. Likewise soils are also an archive or memory of past climates, environments and ecosystems and thus if they are lost these archives of Earth history also will be lost. Soil biodiversity may be greater than aboveground biodiversity; however, our understanding of soil system is incomplete. Pristine soils have begun to be rare natural bodies at the worldwide level. The lack of scientifi cally sound soil biodiversity inventories do not allow us to know the rate of extinctions of soil living organisms, particularly in view of their role in metabolizing and cycling nutrients and compounds in ecosystems. Therefore, soil cover has a vital role in biosphere biogeochemical cycles. Furthermore in view of our lack of knowledge of soil biodiversity, the only way to preserve organisms inhabiting in these natural bodies is to maintain their habitats as pristine as possible"--