The question of how to deal with fractured rock domains has always been on the agenda of geohydrologists. Are Darcy's law and the theory of flow through porous media applicable to fractured rock aquifiers, at least when the flow is assumed to be in the laminar flow range? Is the continuum approach applicable? This subject has also been investigated by reservoir engineers because many important petroleum reservoirs are in fractured rock formations. Of special interest are reservoirs composed of fractured porous rocks, in which the blocks surrounded by the network of fractures are porous. The permeability of such blocks is often rather low, but the porosity, and hence the storage capacity for fluids, is very high. This "double porosity" model for fractured porous rock domains was first introduced in the field of reservoir engineering.;In the past two or three decades, fractured rock domains have received increasing attention not only in reservoir engineering and hydrology, but also in connection with geological isolation of radioactive waste. Locations in both the saturated and unsaturated zones have been under consideration because such repositories are sources of heat and potential

By 2050, the demand for water to sustain world agriculture will increase by seventy-five per cent in order to feed an estimated nine billion inhabitants. Increased amounts of water will be required for irrigation and for industrial and domestic use. Natural ecosystems will be threatened by the expansion of agricultural land and by a reduction in water availability, while climate change will exacerbate the situation. Management of available resources, particularly groundwater, will become more critical and aquifers will need to be managed for the benefit of all. These selected papers were first presented at the International Association of Hydrogeologists, Dijon 2006, and are divided into six themes: large aquifers, resource assessment; large aquifers, water salinity and evolution; karstic and carbonate aquifer systems; geothermal aquifer systems; aquifer contamination studies and aquifer monitoring systems and management. The volume also includes a short biography of Henry Darcy and illustrates his contribution to science. Five invited contributions describe modern methods for estimating the hydraulic conductivity of aquifers.